Laptop: Asus U36SD
Ram: 6 GB
HDD: (C: ) 279 GB + (D: ) 394 GB

I was using my laptop pretty intensively at the time it went BSOD. It started to lag and then it started hanging, and then the BSOD came. This is only the 2nd or 3rd BSOD on this laptop which is 1 year old.
-Livestreams on Google Chrome
-Editing gfx on GIMP
-In DotA 2

The laptop then went into a black screen, while all the status lights are on. It was like that for a while so I pressed the power button to shut it down, then I booted it up. It got past the ASUS logo screen, then to a black screen with an underscore flashing on the top left. (After some reading it appears that it means that there is no OS to boot to)

After several reboots using the power button it was still like that. I then used F1/F2 to go into the BIOS and I could still see the hard-drive listed there in the SATA configuration. (ST9750423AS) There is only this ST97500423AS though, even though I have C: and D:, is that normal, are they just partitions?

So I tried to just save and exit and the same problem still occurred. I then tried to disable ASUS Fancy Start to no avail. Then after several reboots I'm randomly presented with the black screen with grey options to start on Safe Mode or to Start Windows Normally. I selected Safe Mode and it started to list down all the SYSTEM32 files and prepared to start. The start continued into a black screen with the cursor in the center. After a few minutes it rebooted into the ASUS logo screen and this time it went into BIOS after a while, and my hard drive was no longer listed in the BIOS settings. I restarted 2-3 times and still no detection of hard drive, the laptop just automatically goes into BIOS. I shut the laptop down and after a while I tried again, and this time I was presented with the Safe or Start Normally screen again.

This time, I selected Start Windows Normally and the windows 7 logo would not appear. (4 colors going in circles to form into the windows logo)
Then, the windows startup repair wizard appeared, and after letting it repair, the following boot worked and here I am, inside my computer again. I'm creating a system image right now (last one was a month ago) and am rather confused. Here's a HDDScan i did.

http://i48.tinypic.com/1567od3.png

We can't tell exactly what happened during the story that you gave but, based on that data, my vote is that the drive is sick. Several uncorrectable errors have been reported by the drive (and some timeouts). The current reported lack of reallocated or pending sectors suggests that the (sometimes) unreadable sectors did later became readable again.

If it was my drive, I would copy the data that I needed from the drive (it could fail catastrophically at any time) and then replace it.

Of course, you can keep using it until something worse happens, if you want to do that. Just make sure you have recent (verified) backups and know a source for a replacement drive, and then a drive failure is just an inconvenience, not a disaster

Thanks.

Is there any way to further investigate this?

Here's a Speedfan online analysis I did: http://www.hddstatus.com/hdrepshowrepor ... n=7D2D1C7F

I'm using HD Tune to scan for errors right now..

Personally I don't see the value in further investigation. As I said before, there are hints in the SMART data, that the drive has had problems in the past. IMHO it will cost more in time and trouble for you to try to find out more, than to be cautious and replace the drive. You have to decide how much your time and data is worth.

FYI see my comment on this thread, about figures like the "98%" fitness shown on the hddstatus.com link that you gave:
hdd-not-recognized-after-windows-update-beeping-noise-t25454.html?#p171344

If you want more proof that the drive has had problems, then you need to download and install the (free) smartmontools package, run "smartctl -x", and provide the full text output. (It's been a long time since I did that on Windows as I mostly use *nix - you'll need to spend some time yourself on this.) The point is that this command will extract some of the (public) internal error logs from the drive, which can provide evidence about some types of problems. However, I expect that will just confirm what the SMART data has already hinted. If you collect & provide the full output from that smartctl -x command, then I'll review it and give an opinion about what it shows - it's your choice.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 03 20 08 00 00 00 Error: UNC at LBA = 0x03200800 = 52430
848

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:15.748 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:15.747 READ DMA EXT
25 00 00 00 08 00 00 26 6e 98 08 40 00 00:00:15.728 READ DMA EXT
25 00 00 00 02 00 00 26 6e 98 00 40 00 00:00:15.583 READ DMA EXT
25 00 00 00 01 00 00 26 0e 98 00 40 00 00:00:15.581 READ DMA EXT

Error 10 [9] occurred at disk power-on lifetime: 5627 hours (234 days + 11 hours
)
When the command that caused the error occurred, the device was active or idle
.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 03 20 08 00 00 00 Error: UNC at LBA = 0x03200800 = 52430
848

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:13.130 READ DMA EXT
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:10.759 READ DMA EXT
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:08.392 READ DMA EXT
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:06.017 READ DMA EXT
25 00 00 00 01 00 00 26 0e 90 00 40 00 00:00:05.998 READ DMA EXT

Error 9 [8] occurred at disk power-on lifetime: 5627 hours (234 days + 11 hours)

When the command that caused the error occurred, the device was active or idle
.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 03 20 08 00 00 00 Error: UNC at LBA = 0x03200800 = 52430
848

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:10.759 READ DMA EXT
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:08.392 READ DMA EXT
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:06.017 READ DMA EXT
25 00 00 00 01 00 00 26 0e 90 00 40 00 00:00:05.998 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:05.997 READ DMA EXT

Error 8 [7] occurred at disk power-on lifetime: 5627 hours (234 days + 11 hours)

When the command that caused the error occurred, the device was active or idle
.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 03 20 08 00 00 00 Error: UNC at LBA = 0x03200800 = 52430
848

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:08.392 READ DMA EXT
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:06.017 READ DMA EXT
25 00 00 00 01 00 00 26 0e 90 00 40 00 00:00:05.998 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:05.997 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:05.964 READ DMA EXT

Error 7 [6] occurred at disk power-on lifetime: 5627 hours (234 days + 11 hours)

When the command that caused the error occurred, the device was active or idle
.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 03 20 08 00 00 00 Error: UNC at LBA = 0x03200800 = 52430
848

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
25 00 00 00 01 00 00 03 20 08 00 40 00 00:00:06.017 READ DMA EXT
25 00 00 00 01 00 00 26 0e 90 00 40 00 00:00:05.998 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:05.997 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:05.964 READ DMA EXT
25 00 00 00 01 00 00 00 00 00 00 40 00 00:00:05.939 READ DMA EXT

Error 6 [5] occurred at disk power-on lifetime: 5627 hours (234 days + 11 hours)

When the command that caused the error occurred, the device was active or idle
.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 0f dc 9c c0 00 00 Error: UNC at LBA = 0x0fdc9cc0 = 26611
6288

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
60 00 00 00 08 00 00 0f dc 9c c0 40 00 00:05:03.024 READ FPDMA QUEUED
60 00 00 00 29 00 00 03 b8 7d 48 40 00 00:05:03.010 READ FPDMA QUEUED
60 00 00 00 08 00 00 03 81 ff e0 40 00 00:05:03.003 READ FPDMA QUEUED
60 00 00 00 08 00 00 03 23 45 48 40 00 00:05:02.994 READ FPDMA QUEUED
60 00 00 00 11 00 00 07 3d aa 41 40 00 00:05:02.993 READ FPDMA QUEUED

Error 5 [4] occurred at disk power-on lifetime: 5627 hours (234 days + 11 hours)

When the command that caused the error occurred, the device was active or idle
.

After command completion occurred, registers were:
ER -- ST COUNT LBA_48 LH LM LL DV DC
-- -- -- == -- == == == -- -- -- -- --
40 -- 51 00 00 00 00 10 38 02 f8 00 00 Error: UNC at LBA = 0x103802f8 = 27210
6232

Commands leading to the command that caused the error were:
CR FEATR COUNT LBA_48 LH LM LL DV DC Powered_Up_Time Command/Feature_Name
-- == -- == -- == == == -- -- -- -- -- --------------- --------------------
60 00 00 00 08 00 00 10 38 03 08 40 00 00:03:31.609 READ FPDMA QUEUED
60 00 00 00 08 00 00 10 38 02 f8 40 00 00:03:31.598 READ FPDMA QUEUED
60 00 00 00 08 00 00 03 83 28 80 40 00 00:03:31.597 READ FPDMA QUEUED
60 00 00 00 08 00 00 03 83 27 a0 40 00 00:03:31.483 READ FPDMA QUEUED
60 00 00 00 08 00 00 03 83 27 10 40 00 00:03:31.483 READ FPDMA QUEUED

SMART Extended Self-test Log Version: 1 (1 sectors)
Num Test_Description Status Remaining LifeTime(hours) LBA
_of_first_error
# 1 Short offline Completed without error 00% 5636 -
# 2 Short offline Completed without error 00% 3731 -

SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

SCT Status Version: 3
SCT Version (vendor specific): 522 (0x020a)
SCT Support Level: 1
Device State: Active (0)
Current Temperature: 36 Celsius
Power Cycle Min/Max Temperature: 28/48 Celsius
Lifetime Min/Max Temperature: 19/48 Celsius
Lifetime Average Temperature: 36 Celsius
Under/Over Temperature Limit Count: 0/0
SCT Temperature History Version: 2
Temperature Sampling Period: 1 minute
Temperature Logging Interval: 30 minutes
Min/Max recommended Temperature: 14/55 Celsius
Min/Max Temperature Limit: 10/60 Celsius
Temperature History Size (Index): 128 (53)

Index Estimated Time Temperature Celsius
54 2013-03-04 13:00 38 *******************
55 2013-03-04 13:30 38 *******************
56 2013-03-04 14:00 37 ******************
57 2013-03-04 14:30 38 *******************
58 2013-03-04 15:00 37 ******************
... ..( 4 skipped). .. ******************
63 2013-03-04 17:30 37 ******************
64 2013-03-04 18:00 36 *****************
65 2013-03-04 18:30 ? -
66 2013-03-04 19:00 28 *********
67 2013-03-04 19:30 ? -
68 2013-03-04 20:00 28 *********
69 2013-03-04 20:30 36 *****************
70 2013-03-04 21:00 36 *****************
71 2013-03-04 21:30 38 *******************
... ..( 2 skipped). .. *******************
74 2013-03-04 23:00 38 *******************
75 2013-03-04 23:30 39 ********************
76 2013-03-05 00:00 37 ******************
77 2013-03-05 00:30 36 *****************
78 2013-03-05 01:00 36 *****************
79 2013-03-05 01:30 36 *****************
80 2013-03-05 02:00 37 ******************
81 2013-03-05 02:30 38 *******************
82 2013-03-05 03:00 38 *******************
83 2013-03-05 03:30 39 ********************
84 2013-03-05 04:00 37 ******************
85 2013-03-05 04:30 38 *******************
86 2013-03-05 05:00 37 ******************
87 2013-03-05 05:30 37 ******************
88 2013-03-05 06:00 36 *****************
89 2013-03-05 06:30 37 ******************
90 2013-03-05 07:00 36 *****************
91 2013-03-05 07:30 ? -
92 2013-03-05 08:00 36 *****************
93 2013-03-05 08:30 ? -
94 2013-03-05 09:00 36 *****************
95 2013-03-05 09:30 ? -
96 2013-03-05 10:00 36 *****************
97 2013-03-05 10:30 ? -
98 2013-03-05 11:00 36 *****************
99 2013-03-05 11:30 ? -
100 2013-03-05 12:00 36 *****************
101 2013-03-05 12:30 ? -
102 2013-03-05 13:00 36 *****************
103 2013-03-05 13:30 ? -
104 2013-03-05 14:00 36 *****************
105 2013-03-05 14:30 ? -
106 2013-03-05 15:00 36 *****************
107 2013-03-05 15:30 ? -
108 2013-03-05 16:00 37 ******************
109 2013-03-05 16:30 ? -
110 2013-03-05 17:00 37 ******************
111 2013-03-05 17:30 ? -
112 2013-03-05 18:00 35 ****************
113 2013-03-05 18:30 ? -
114 2013-03-05 19:00 35 ****************
115 2013-03-05 19:30 ? -
116 2013-03-05 20:00 35 ****************
117 2013-03-05 20:30 ? -
118 2013-03-05 21:00 35 ****************
119 2013-03-05 21:30 ? -
120 2013-03-05 22:00 37 ******************
121 2013-03-05 22:30 ? -
122 2013-03-05 23:00 37 ******************
123 2013-03-05 23:30 ? -
124 2013-03-06 00:00 38 *******************
125 2013-03-06 00:30 ? -
126 2013-03-06 01:00 38 *******************
127 2013-03-06 01:30 ? -
0 2013-03-06 02:00 33 **************
1 2013-03-06 02:30 ? -
2 2013-03-06 03:00 33 **************
3 2013-03-06 03:30 ? -
4 2013-03-06 04:00 35 ****************
5 2013-03-06 04:30 ? -
6 2013-03-06 05:00 34 ***************
7 2013-03-06 05:30 40 *********************
8 2013-03-06 06:00 41 **********************
9 2013-03-06 06:30 42 ***********************
... ..( 4 skipped). .. ***********************
14 2013-03-06 09:00 42 ***********************
15 2013-03-06 09:30 37 ******************
16 2013-03-06 10:00 39 ********************
17 2013-03-06 10:30 ? -
18 2013-03-06 11:00 28 *********
19 2013-03-06 11:30 ? -
20 2013-03-06 12:00 28 *********
21 2013-03-06 12:30 40 *********************
22 2013-03-06 13:00 44 *************************
23 2013-03-06 13:30 45 **************************
24 2013-03-06 14:00 47 ****************************
25 2013-03-06 14:30 48 *****************************
26 2013-03-06 15:00 48 *****************************
27 2013-03-06 15:30 48 *****************************
28 2013-03-06 16:00 45 **************************
29 2013-03-06 16:30 42 ***********************
30 2013-03-06 17:00 47 ****************************
31 2013-03-06 17:30 47 ****************************
32 2013-03-06 18:00 44 *************************
33 2013-03-06 18:30 43 ************************
34 2013-03-06 19:00 44 *************************
35 2013-03-06 19:30 40 *********************
36 2013-03-06 20:00 39 ********************
37 2013-03-06 20:30 42 ***********************
... ..( 3 skipped). .. ***********************
41 2013-03-06 22:30 42 ***********************
42 2013-03-06 23:00 41 **********************
43 2013-03-06 23:30 37 ******************
44 2013-03-07 00:00 36 *****************
... ..( 8 skipped). .. *****************
53 2013-03-07 04:30 36 *****************

SCT Error Recovery Control:
Read: Disabled
Write: Disabled

Device Statistics (GP Log 0x04) not supported

SATA Phy Event Counters (GP Log 0x11)
ID Size Value Description
0x000a 2 1 Device-to-host register FISes sent due to a COMRESET
0x0001 2 0 Command failed due to ICRC error
0x0003 2 0 R_ERR response for device-to-host data FIS
0x0004 2 0 R_ERR response for host-to-device data FIS
0x0006 2 0 R_ERR response for device-to-host non-data FIS
0x0007 2 0 R_ERR response for host-to-device non-data FIS


Exitcode: 64 (0x40)
Type <return> to exit:

Thanks. Although that wasn't the full output from smartctl, the error logs clearly show UNC errors for multiple sectors, shortly before (i.e. within the same 1 hr power-on interval as) the HDD Scan SMART data that you provided at the beginning. There is more opinion I could give, but the short version is that this is just what I expected - the drive's internal error log confirms that the drive is misbehaving, as suggested by hints in the SMART data.

I believe the cause is most likely to be an internal drive problem, although there is a slim chance that the cause is external (e.g. power). Your only way to confirm / deny each possibility would be to try many times to cause similar problems (in order to find out how often these problems occur, and so get an idea of roughly how often they can be expected). Then try a different drive in that laptop (and, ideally, move that "suspect" drive to a known-good PC / laptop), do the same things with your laptop again (with a new drive inside), and see if problems still occur at the same frequency. If so, it's the laptop; if not, then it was probably the drive.

There is more to the troubleshooting than this, but the full explanations would take too long. I hope this explains why, in reality, it makes most sense to replace the drive, if you care about trying to prevent a repeat of the problem you originally described. Good luck with whatever you decide to do