I recently reformatted my hard drive because i could't get my copy of half life 2 to start. I immediately had troubles with my ati all in wonder 9800. when i would start the game, it would play the intro and then all of a sudden the monitor would go into power save moe and i would have to reset the computer. At first this happened only when playing the game but now it happens every haalf hour or so even if i am just surfing the internet. Whats going on?

Check your temperatures and post them.

Does your box need a cleaning?

cpu and hard drive are around 35, but i dont know how to check the temperature of my video card. My box could definitely use a cleaning though.

Those temps are great, in fact I wonder if they are accurate, especially the hard drive. Mine run up around 50C.

It could be the video card, but I don't know how to check it either, maybe someone else does. Is the fan running at a good speed?

But anyway I would suggest checking your memory.
Memory test
http://memtest86.com/
There is a version to create a bootable floppy diskette and/or an ISO for creating a CD.
Run it for a few hours, or better yet overnight, and any failures are unacceptable.

If you clean the box, do not use a vacuum cleaner, they can cause static problems. A can of compressed air is best.

ATI recommends a 300-Watt power supply or greater to ensure normal system operation where a number of other internal devices are installed. Also what Directx version you may need to have x9 installed.