Locking problems with UT and QIII

[SlimShady]

hey guys, i currently have a tbird 800 and a geforce 2 64mb card using the Digital Jesus drivers (see madonion.com) and i have a major prob with QIII and UT. the games will just randomly lock up on me at some point. nothing is overclocked, and i am using the via 4.24 drivers. it will run 3dmark endless times, but it has trouble with these games. and i think it has trouble with other games as well. i have tried different versions of the NVIDIA drivers with no luck. i also turned down all of the bells and whistles in my BIOS to no avail. any idea what to check next?