Slow computer in games, formatted harddrive and reinstalled Windows 7, STILL slo

Hi a couple weeks ago I would get a constant terrible lag in World of Warcraft it would be down to 2fps or 1fps and it would be like that for 1-2 minutes then go back to normal for like 5. It was very difficult to play with, same for Starcraft 2. So I got sick of it and I wiped my harddrive and reinstalled my Windows 7. I opened up Starcraft and it was being VERY slow again can somebody PLEASE help me out? I used to be able to play video games with no problem at all and yes I installed all my drivers and yes my graphics are even on low. Thank you.

My specs are:
AMD Athlon(tm)II x4 620 Processor 2.60GHz
6GB of ram.
512MB piece of *** graphics card, still decent enough like I said before I was able to play just fine a while ago.
And Windows 7 64-bit. I don't really know what else to put down that's a necessity so, thank you.

Howdy. Could be that your machine is over-heating. Clean it of all dust and make sure the cooling fans are not blocked off. Overheating can sometimes slow your machine down by 20%! You should also run a defrag with a really a good defragger like diskeeper, it's much more faster and advanced than the in-built and I think you can get a free trial from their website.

I've already cleaned it out. Used the air can and sprayed out every fan, and cleaned out my computer entirely. Not sure what the problem is.

Have you tried any other games to see if they lagged as well? Both games you mentioned run off Blizzard's Battle.net; it might have been them or your internet connection to battle.net that were having the issue.