gant get beyond level 1 on quake 4

[fistdog]

See specs below for rig. Everytime I go on Quake 4, I can't get beyond level 1. When I try to, the program closes, EVERYTIME!
I uninstalled and reinstalled the game but the same thing happens

please help - thx - Sam

Athlon 2900+ and Abit KV7-V Motherboard
160GB Seagate Serial ATA HDD
Case, 420W Power Supply, Heatsink, Fans, Floppy, CD Drive 2
Rosewill Radeon 9800 Pro and 1GB RAM
Acer 17" LCD Monitor
Lite-on 16x DVD Burner and Altec Lansing Speakers