These are difficult problems to solve, especially over the internet. Let me ask you a few things. Does your computer hang when U install another OS? (Think you mentioned you had WinME)
You could try removing all hardware (physically) from the computer with the exception of your video card ofcoarse. Restart. Does your system still freeze? Do you have multiple memory modules? You could try removing one (or a pair) and see if the same happens. Swap the memory modules and try again.
Try borrowing a video card from a friend and try if you system still hangs with his videocard. This all with MINIMAL hardware in your PC. No Soundcards, Network Adapters, Modems, SCSI cards. Take em all out.
Its all time consuming trial and error. Hope this helps a bit.
Kind regards,
Willem Moolenaar