I have been getting big problem when playing games. My PC will randomly blue screen crash when i play a game and sometimes happen when watching a video. Now i have all updates for sound and gfx card and the mainboard i believe. I found a conflict in my device manager in the system devices list: Pci bus. It says Memory Range C0000000 - FEBFFFFF not available. I don't know exactly what it does but all i know is it ain't good. Does anyone have an idea? thx.

Gigabyte GA-VM900M Mainboard

In BIOS, set the memory Volage to RAM MFG. specs. or bump the memory voltage up a notch. The PCI bus has nothing to do with your system crashes.

I seem to have a problem doing that. In my bios there doesn't seem to be a option to change the voltage on my ram. It is set to 1.8 volts i think but can't select it because its grayed out. Is there a way to turn the option on?

Grayed out usually means the Mfg. has locked you out of that BIOS function or tweak. If your memory is rated at 2.0- 2.1v from the MFG. for example, and your board is supplying 1.8v that can likely cause your crashing problem. You might run Memtest86 and check for errors. RAM is a likely cause of system crashes when running software including games and DVDs. Get memtest here with Ultimate bootdisk:

http://www.majorgeeks.com/Ultimate_Boot_CD_d4981.html

thx for helping out. I tested my ram many times but showed up no errors. The brand of my ram is dynet and i checked out the gigabyte site of supported ram chips and i don't see it in the list. Even tho it doesn't show any problem in the mem test i guess my mainboard and this ram arn't happy together i'm gona runs some more tests. If not i might go shop for some quality ram. By the way i didn't pick this ram when i bought my pc. But anyway thx again for your help. I'll let you know how it turns out

Its all good now. It must of been my ram it was DDR II 667mhz. I replace my 2gig for 800mhz ram and now its running good now.

That's great. System crashes that occur when running software applications (games, etc.) are often caused by defective, undervolted, faulty RAM. That is the first place you look when you have your type of system crash (as you described it).