Windows XP Severe Errors, Please assist!

Hi. I recently upgraded from:
MSI MS-6380E
AthlonXP 2000 (running at 1.67GHZ)
256mb Sapphire Radeon X700
1 gigabyte of ram This setup had NO problems
Sound Blaster Audigy SE sound card
NetGear GA311 Gigabit LAN card
Windows XP Pro SP1
A 20GB Hard Drive
A 40GB Hard Drive
Power Supply: 400W Codegen
to this:

Board: Gigabyte GA8I848P-G
Processor: 2.4GHZ Pentium 4
Video Card: Same. Sapphire Radeon X700, 256MB
HDD:80GB Maxtor
Sound Card: Same I can run this setup for around 5-15 minutes before complete lock.
LAN Card: Same
RAM: Same Amount. 1 512 Stick, 2 256 sticks
O\S: Windows XP Professional SP2
Power Supply: 450W Hercules

Now, every time i try to play a game, or even use my computer for that matter, it freezes up after about 15 minutes of optimal performance. Please assist!

Regards, Cianan J.T. Puckett

The last time I had an issue like this, it ended up being the video card. Downloaded latest drivers and still didn't work properly. Then I came across www.omegadrivers.net and tried his drivers out (after doing a full clean-up of the existing drivers). Well, not only did this solve my problem, but for years now I've been using his drivers without problems.