Problem with running games in fullscreen

[Guest]

Hello.

PC Spec
CPU: Intel core 2 duo E8500 3.16GHz
Motherboard: P5Q3 Deluxe/wifi
RAM: 2x 2GB OCZ DDR3PC3-16000 Platinum Enhanced Bandwidth Edition (mounted in the orange slots)
Graphic card: HD Radeon 4870 x2
HD: Velociraptor 150gb

OS: Windows Vista home premium 64bit
DirectX 10

I'm having some weird problem with my new-built PC and have been trying to figure out how to solve them but so far, no luck at all.
Hope you guys can help me figure out what problem can it be and how can I solve it.
My problem is basically all games crashes everytime I start them in fullscreen. Sometimes the whole PC crashes with a echo sounds from the speaker. Moreover, the PC crashes time to time sometimes without even starting games in fullscreen. I have tried using different bios and update the bios and every possible drivers but the problem still persists.
I'm not sure what can it be, but I suppose it might be something related with drivers or the memory.
I have everything in auto configuration, so my 1600mhz OCZ RAM only run at 1024mhz. I am not sure if this can be the problem though.
Please, if anyone can give me a light about this problem, I will be gladly thankful. I have been trying to fix this since forever and I am really frustrated I cannot enjoy my PC at its full.

Thanks!

 

[Guest]

Game crash to desktop

Thanks I will try that out!

 

[Guest]

Hi again.
The memory remap feature were enabled all the time at default bio settings. and I just finish with doing the memtest for 4h and 30mins, the result were 8 passes and 0 errors. Does that mean the problem is not my memory at all?. Moreover after doing the memtest the problem stil exist :/.

 

[Guest]

I just updated my graphic card to the latest driver and now I have another problem whenever I start a game(doesnt matter if it's in fullscreen or not) it gives a fatal error. like Error "Direct3D Render Error:", "<< error >> can't create device (887686a)", "CRITICAL ERROR: Couldnt initialize 3D enviroment".....

Edit: nwm fixed it. only the fullscreen problem left, going to try to fix it with this way

"Clear your cmos take off the battery put the jumper to 2&3 for 10mins
Now set your ram TIMING and VOLTAGE manually according to your ram manufacturer( look at the sticker on the side of your ram)
Set your NB Voltage to 1.26