Club3D Radeon 9600 256mb

Hi Mates,

i have the following problem and i hope somebody could help me

I bought last days a Club3D Radeon 9600Pro 256mb.
And I installed it correctly:

Bios update, newest
MB Chipset drivers, newest DirectX, Catalyst 3.9, and I installed my System new;

Problem: when I play a Game (Zero Hour, BG2....) after about 1-5 minutes there comes a black screen and refresh rate turns back to 30 - 50HZ; and then come an error (Zero Hour: VPU failure; BG2 3D problems turns back 2 Software rendering ) or the PC reboot´s himself or he [-peep-] up;

PLZ HELP !

System

ASRock MB
Athlon XP 2600+
1 GB Ram
Club3D Radeon 9600pro Value Edition 256mb
Nokia 445XPro 21" Monitor
80GB/8 mb Cache Diamond Maxtor HDD

Doc