My preliminary guess (just based on your first post and the nature of the bsod) would be ram or hd. Let's troubleshoot those two first:
To check the ram, download memtest (http://www.memtest.org/
). Burn it to a cd using a dedicated .iso burning utility (http://www.petri.co.il/how_to_write_iso_files_to_cd.htm
), make sure the cd drive is at the top of the boot order in bios, then boot to the newly created cd and run the utility.
To run checkdisk, right-click on a command prompt icon and open as administrator. In the command prompt window type:chkdsk /r
(then press ENTER). You'll be told the disk is in use and asked if you want to run checkdisk on the next boot. Say yes, exit the command prompt window, and reboot.