Good Morning Everyone

First time here and would like to ask for your help

I build a PC for gamer and here is what I have:

Motherboard: Asus P5B – SE
CPU: Duo Core E6850
Ram: 4 GB
Graphic CARD: XFX 8800GT then Radeo X1650
Power Supply: 680 W then 550 W
Running Windows XP
Test Game Call of Duty 2 and Call of Duty 4

First, when I use the XFX 8800, the PC SEEMS to be alright at first. Then I install game and play it (testing both games), the PC becomes every unstable; Crash / Reboot itself and if I turn OFF the Automatic Reboot, the windows crash with blue screen and I have the message as IQL_NOT_EQL_OR_LESS … Then I start having this problem EVEN without playing game… (I install the game to my laptop and playing just fine without any problem for both games)

I swap the graphic card to Radeo X1650 and also the Power Supply Unit. Reinstall the windows and just the games… I can be able to play COD 2 without any windows disturbed. However, when I play COD 4, the game Crash and Freeze… and also the PC reboot itself. I did not turn of the auto reboot this time.

I have been doing research and people are talking about OVERCLOCKING and SPEED UP the Fan… I am not familiar with this subject so I am wonder if ANYONE can help me on this problem:

1.Have any one seen a similar problem and find out the solution?
2.Should I overclocking and Speed up the Fan? I am not sure how hot is too hot for the CPU and Graphic Card. And will it give my PC even more unstable?
3.How do I test my Asus P5B SE if my Mother board having any defect problem?

Thanks a lot
with the 8800GT, did you remember to plug in the supplmentary power connector?

you should not need to INCREASE the fan speed on a video card running at stock speeds.