I had the same problems. First, I ran memtest, even though the ram doesn't really pertain to this problem, but it's always nice to eliminate choices, and got 0 errors like I expected. Then, I switched my monitor with my dad's (15 inch Sony LCD), and had the same old problems. At this point, considering I reformatted, it can't be software, my ram, or my monitor. The only logical things it could be are my mobo, my video card, or my PSU. But I'm lenaing towards the graphics card or the PSU. And I don't wanna take it into a shop because I've already had too many problems with this computer, the biggest being me RMA'ing my ram back to newegg. So I'm trying not to even tell my dad about this since he'll probably get really mad. Any ideas? And I'll try not to make too many more topics, actually the mods can just delete the previous two. Thanks again.
edit: here's a link the second topic I made, which has a link to the first topic in the second or third post I believe.