Summary: The file structures on NTFS partitions of two separate HDs are corrupted, but my FAT32 partitions are fine. Details: A few months ago, I installed a new 80gig Seagate SATA harddrive for my budget/backup computer. Since the beginning I experienced random crashes and reboots every few days. I ran Windows error checking tools and nothing showed up. I also checked the RAM using memtest86 and it came back fine. I assumed it was a weak power supply that I took from an old computer. But when I replaced it with a new, more powerful power supply, it continued to crash. I then downloaded Seagate's Diagnostic tools and ran that. It reported that my main Windows partition (NTFS) failed the file structure test with critical errors. I ran Windows error tools (file system errors and bad sector checks) and this time it seemed to find some problems that it attempted to fix. Well, I ran the Seagate tool again and it still failed the file structure test. I created a new FAT32 partition on the HD and backed up my files. I ran the Seagate tool again, and the NTFS partition failed, while the FAT32 partition passed. Seagate's tech support suggested I run chkdsk with the "f" and "r" options. I did this and it completely ruined my Windows install. At this point, I decided to use an old spare ATA HD I had to reinstall Windows and retrieve my files off the Seagate HD. I copied my files onto the old HD which had been freshly formatted (as NTFS) and everything seemed fine. My plan was to wipe the Seagate clean and start all over. But, I ran the Seagate Tool on the old spare HD and it failed the file structure test also. Again I created a FAT32 partition and copied my files to it, and it passed the file structure test. Can anyone explain whats going on here? Could I have a file that is corrupting my file system? Why does it only happen on NTFS partitions? How can I fix it? Sorry this had to be so long and thanks in advance.