Thanks everyone! This thread helped me get my fully drive capacity back on a Maxtor (Seagate?) HDD
Let me explain how I stuffed up and what I eventually did to put things right in a bit of detail, as the extra info might help someone?
1. I had tried to replace the duff Maxtor 200 GB ATA/133 HDD (with severe head probs) in a Maxtor "1-Touch" case with a band new Maxtor STM332060A 320 GB PATA drive.
2. I connected the "1-Touch" case to a PC running XP MCE via USB and it maide all sorts of funny noises, so I quickly shut down, removed the drive and connected it directly via IDE cable as the only drive.
3. After booting the PC with Partition Commander CD, the drive mis-reported its capacity as 131071 MB.
4. I tried using SeaTools Desktop v3.0 (2 floppies) and SeaTools for DOS v2.136 (1 floppy) but neither could set the capacity of the drive back to native maximum. It seems that Maxtor drives are perhaps really OEM'd Seagate?
5, I then tried lots of methods to try and get the proper capacity back, including zeroing out LBA-3 using Roadkil's Sector Editor, then trying to reset the Native Max Capacity back to what it should be with various DOS boot CD tools, including the Hiitachi Feature Tool v2.13 and the HDDGURU Magic Boot Disk v2.0, but nothing would let me change it, the command always failed.
4. After finding this thread and trying HDAT2 v4.53 booted from CD, with the info in this thread, I finally managed to set the capacity right using the 48/28 bit LBA trick. When first viewed, its seems that the drive was reporting it had a 48-bit LBA but was acting as having a 28-bit one. When I first tried to change the LBA to 28-bit, the command failed, so I experimented with other stuff including using F7 Restore all on the 48-bit Address feature set.
5. After powering down and restarting HDAT2, I could successfully change the LBA to 28-bit from the Set Max Address item using L to set LBA mode.
6. After rebooting again, HDAT2 now shows the correct drive capacity of 320.07 GB in Device Infformation and under Set Max Address screen, even though it is properly using 48-bits LBA mode, not the the 28-bit set prior to the reboot. So now the problem has been resolved and both the Native area and User area have 625142448 sectors as it should be.
Thanks again for putting me on the right track!