I had a very bad problem with my system, Whenever i would play a 2d game: Age of Empires: The conqueres it would stall in like 3 minutes, that was really ticking me off. It took me 2 weeks to fix it. I even talked to microsoft for 3 hours. My system is:

Abit KT7-Raid
AMD-"Thunderbird" 1000MHZ-better than Pentium by far!!!
Creative Labs 3D annihilator Pro (DDR Geforce)
Sound Blaster X-Gamer
256mbs of PC150MHz Kingmax RAM
20 gig 5400rpm hard drive (i'm looking into getting a 45 gig)
ZIp 100
52x Kenwood ZEN cd-rom
Creative 8432
AOpen PCI Modem 56k
-Thats about it-

Well like i said it stalled i tryed all via drivers reformated like 4 times and reformated part by part, and it was all due to the agp being at 4x when i switched it back to 2x I have no more problems!

PC_MaN