I had a friend's HP Pavilion desktop computer that would crash soon after boot with a Blue Screen Of Death STOP 0x00000050 error. I ran on-board diagnostics from the BIOS and everything passed. I booted with memtest and ran it overnight without error. I did not want to just reformat the drive since it had files that needed to be saved. I removed the hard drive and added it to a Windows XP computer as an external drive with a USB adapter. When attempting to mount the drive, the computer would slow to a crawl and eventually freeze, with the System process using 99% of the CPU. It would report that the System Volume Information area was corrupt and suggested repairing it with a CHKDSK. But I could not do that with a frozen system! So, just because I had one conveniently nearby, I attached the drive and the USB adapter to a Mac mini running OS X 10.5. It could read and mount the drive with no problems. I was able to backup the files to the Mac mini successfully. But putting it back on the PC failed again. So I attached it to the Mac and erased the Windows partition (by formatting it as FAT, since the Mac cannot write NTFS volumes.) Finally I installed it as the internal drive in the HP Pavilion, and used the boot option to perform a Restore to Factory Condition from the HP partition. It worked. Problem solved, thank you Apple.