somegamer786: I have Used the defrag.I probably should just delete all programs (not including the preinstalled ones) and start over. This might of happened 'cause of Vista :P
Navagon: If you don't have a lot of free space then that would certainly explain it. I'd also recommend taking a look at your virtual memory settings and see if you can't increase that a bit.
Yeah, especially if the poster has Windows Vista.
It really needs that extra disk space to work properly.
At some point, I had less than 30 GB to spare and my comp froze often.
Finally, I couldn't take it anymore and resolved myself to overpay ~20$ for an additional external hard drive during a special. I put my GOG collection on it and let's just say that freed over 100 GB of space (yes, my collection is big) and then the stability problems I experienced went away.
Try to keep your available disk space above 40 GB if you can with Vista.
Protoss: Possibly your firewall eats up a CPU, check for that in the task manager. If so, there is nothing to solve that short of disabling or uninstalling the firewall.
KOC: I had this problem recently on both my PC's: After I had noticed the high CPU usage, I closed my firewall / security suite and everything was at least ten times faster. I then switched to another one.
Definitely worth a shot to test performance - just go offline before you shut it down.
I use Webroot for my Windows antivirus.
It's pretty lean.
The installer is like less than 5MB and it scans in less than 5 minutes.
The other lean alternative I know of is Eset, but I hate their guts, because their Antivirus behaves like spamware when your subscription expires (it's hell to uninstall and it keeps giving you those annoying popups that take the focus away from whatever else is running... great fun when you are playing a racing game).
When I got Webroot, I almost felt like sending Eset's customer service a message: "Hey, thanks for the non-stop advice you gave me about getting an up-to-date antivirus subscription. I did, just not with you."