My PC all of a sudden lags on all games. Answered
Here's what happened. I got on today and started up MW2 on my PC. I had just installed a new mod, so i thought nothing of it when it lagged down to 20 FPS, perhaps, when it usually runs at 40-60 FPS. I got bored eventually and went to organize my PC, which included uninstalling a lot of old programs and making new folders. I decided to play borderlands when I was done. I noticed there was a considerable difference in frame rate from the previous day. Same thing with all of my other games, Minecraft, HL2 and all others. The only thing i did overnight was install that MW2 mod through bittorrent ( don't worry, it's legal. Alteriwnet, google it.) I've played around with my GFX card, AMD Raedeon 6540, and no dice. I've played with the clock in catalyst to no avail. I've installed game booster and boosted, but i can't get the lag to go away. The best results I've had are ending one of the 2 processes named wininitt.exe. My FPS almost got back to normal. I Think it has something to do with graphics, as nothing else is really slowed down. Also, I've tried uninstalling the MW2 mod. I played around with my windows 7 theme, too.
Intel firstname.lastname@example.org GHz Dual core
4 GB ram
AMD Raedeon HD 6450 GFX
Windows 7 Home premium
The lag has been abolished. I don't know how, but it's gone. I did not touch my computer for a long time, iI guess to wait it out, but i'm not the only user of my computer, so it was used.
Protips for people coming to this thread because they have the same problem,
Scan for viruses
Do regular HDD cleaning, i.e defragment, delete old files, registry clean.
Lower GFX settings
Clean the computer's internals