Windows XP crashes

I have a DFI AK75-EC mb most updated bios with a duron 950, nvidia e-g-force4 agp, 256 kingston ram, 120 gig maxtor. I have tried to install xp and it works ok for a short time then unexpectedly reboots and corrupts the data. i have changed the video card (another older nvidia), ram and hard drive, downloaded all microsoft patches to the same avail. after several sucessful installions and crashes on 2 different drives, i now cannot even recover the hard drives, on the post test they are garbled as ("LaXnR" instead of Maxtor) with funky characters as the serial number and identified as wrong capacities. i put my windows 2000 (maxtor)hard drive back in my system and it works fine. I goin crazy, any help would be most appreciated.
Thanks,
Sid

Bad disk drive?

use a 98 boot floppy,(fdisk) remove all the partitions, format, (format C: /S)then drop in the xp cd, if a legal copy will boot from cd, if not some of the problem is discovered, copies from kazaa and the like are getting infected with all manor of virus. format in ntfs (full) install again.