i have Hitachi hdd with capacity 500 GB. from the past 2 months i am having blue screen of death. i searched many forums and they suggested to get my hdd and ram tested. please help. specifications are:
Operating System: Windows7 Ultimate
motherboard: Intel
processor: i3 3.10Gh
BIOS VERSION: INTEL CORP. BEH6110H.86A.0016.2011.0118.1128
SMBIOS VERSION: 2.6
mobo model is DH61WW_

If data vital send to data recovery company where they will clone drive and recover data for you. For do it yourself the procedure is to use another working computer with a fresh hard drive as a target at least a large as what you have. You can download a program such as MHDD from this site that knows how to handle the likely bad sectors you may encounter while duplicating. You can then copy the files recovered from the duplicate. If no major damage they will be ready to go. If further logical damage a product such as R-Studio will recover them at minimal expense. I dont suggest stressing the drive further untill you know it is not failing. Checking computers ram is great- buy dont risk your data using this hard drive until you know the cause. My best guess- and it is only a suspicion until disproven: blue screen caused by damaged file by failing sector. IF this is the case then further attempts to fix problem tend to do more damage than help.

there are no bad sectors on my hard drive. i checked it many a times. please suggest something

Yes I would be looking at a) a new power supply, and
b) the capacitors on the motherboard.

random crashes are a very common indicator of these, along with RAM issues.

A "STOP" code would help to diagnose the problem. You might have to disable auto-restart on error in the BIOS settings. To determine whether it's a hardware or software problem, boot a Linux live CD and see if it reboots with that, too. If not, it's a Windows problem and there are many tech support sites to turn to for help, but this isn't one of them.

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Sabo Computer Repairs & Data Recovery

Also look in the windows event log.
I/O errors can mean hard disk problems
Appcrash errors can mean corrupted apps/windows or bad ram, or other things
errors from drivers show up here as well, lots of video card errors Ive seen lately.
lots of times the BSOD error in eventlog will show what .dll caused the error and this can sometimes be traced back to an app, or windows.

IMHO the title of the thread is wrongly titles. No indication exists it has anything to do with the HDD yet.

cheers

if you have elimented the hard drive physically being the cause then you need to continue with each of the items mentioned in prior posts. Most common faults are dirt clogging or bad fans on graphics cards and cpu. Drivers for graphics cards. OS software damaged. Ram faulty. Motherboard. Power supply. This is aproxamate order that I have experianced. It is always time consuming to track down. Check log and see if its same fault each time or truely random will give a much needed direction to turn. Same is usually drivers/OS different is hardware issues.