Game crashes with new harddrive

SYS: Athlon 1800+, 256 DDR2700+ 256 DDR2700 RAM, ATI 8500LE 128DDR, SB Live etc. etc. etc.
I recently installed a new 80g (WD) hd, and my games: Ghost Recon, Sim4, Splinter Cell will not run properly. The games will initiate but game play is limited due to system crash (after 5 mins of play). On system crash, the screen shifts from XP desktop to game screen at a high frequency, an almost psychedelic effect OR it remains black. Anyway- this is a serious issue since I have reinstalled the ATI drivers, Direct X 9, many times.
For some reason, my system is stable surfing the net, or watching videos, or applications: Office XP, Photoshop, but in games, it dies. The games were working on my 40g (Maxtor) drive, before I changed over to the new 80g drive. All programs and apps were reinstalled.
Do you know the reason? It has been three weeks now, and I cannot game!
FUBAR