This my sons computer. He has a radeon 1650pro graphics card 512mb. When he plays world of warcraft or oblivion the screen shuts off and the light turns to an amber color. What should we do and let me know if more info is needed. Thanks

Could be a couple things. A cheap power supply that could be over its amp limit on the 12v+ rail when the gpu has to use power causing the gpu to trip or shutdown. It could be that the gpu is getting overheated due to a faulty fan or poor air flow throughout the case. First thing i would check is the power supply and the requirments to run that type of card on a power supply. Normally it's 300watts or higher and 16amps or higher for those types of cards. Then i would check the gpu temps on it by using a simple tool like ATI Tool which is free and you can find it on google and do a test to see if the gpu temps get real high to the point where the test fails within 15 minutes into it. If it does fail and your power supply meets the gpu requirments then i would check the gpu fan next to see if it's failing at any point, if it does replace it.

Thanks for the info. Will let you know what we find out. Also is there any way to find out what power supply he has because there is no name plate or anything on it.

you will have to look at the sticker on the side of the power supply when you open up your case.

i have the same problem too... I have 2 HDD one is 20gig Master and a 80gig Slave. it boots perfectly until the WELCOME sign appears then suddenly the monitor shuts down(monitor turns off) but the CPU continues to run properly... until i rearrange the wire so that the 80gig will be the Master and the 20gig will be the slave and it works perfectly fine... i think its a VIRUS or something need help thanks..