Video Problem

I got through training, but during the first mission the game the monitor would shut off, but the game was still running?
I reinstalled my video drivers with the ATI hotfix for COD but nothing.

Any suggestion?

Operating System: Windows XP Professional (5.1, Build 2600) Service Pack 1
Language: English (Regional Setting: English)
System Manufacturer: VIA Technologies, Inc.
System Model: KT333-8233
BIOS: Phoenix - AwardBIOS v6.00PG
Processor: AMD Athlon™ XP 2800+, MMX, 3DNow, ~2.9GHz
Memory: 1052MB RAM
Page File: 130MB used, 952MB available
DirectX Version: DirectX 9.0b (4.09.0000.0902)

the video card is a Radeon 9700 Pro