This has happened twice, with two different hard drives, each of which was attached as the only drive (master) on IDE 2:
In the middle of writing some files to the drive, the file structure on the drive suddenly gets totally screwed up. If I look at the drive contents in Explorer, I see garbage characters instead of the folder names that should be there. When I reboot, the drive can no longer be accessed. I think what has happened is that the boot sector, or FAT tables, or both, have been overwritten. The partition table info seems to be OK, though (as viewed in fdisk).
If I use a utility to view data in drive clusters, it seems like there is no valid boot sector, and I cannot find the FAT tables. The file data is still there, for the most part, though it is hard to retrieve without the FAT table info.
With the second drive, it seemed like this drive problem happened just as I was passing 32 GB of data on the disk, which made me begin to wonder if there was a bug in the BIOS related to the 32 GB limit - tho' the BIOS does report the hard drive size correctly.
The first drive was a 40gig, second was a brand new 80gig. My mobo is an Asus with KT133 chipset. I am using an old Dell 250W power supply.
BTW, I reformatted the second drive and have been using for a couple of weeks now with no problems - have gotten up to about 20gig of data on the drive now.
Can someone please suggest what might be wrong here? Can the power supply cause this kind of a problem? Or bad cables or mobo or what?