Windows performance while running heavy programmes

Hi guys,
This is my first posting to any forum about PC. My trouble is that when I download media files using download manager or p2p software my computer doesn't perform like earlier after next boot. Even I delete OB* files (Incomplete downloaded files). Checking disk,defragmentation,deleting unnecessary files, did every thing then started far cry 2 (Game) which worked ideal earlier but takes a lot of time while loading, same with windows start up . I reinstall windows and problem is resolved. It happened thrice and every time i reinstalled windows. Please help me again I am having same problem. Thanks

 

G'Day Sibtain Ali,

What Internet Security do you have installed and active while downloading via P2P etc. ?
Also which P2P are you using ?

pcbugfixer

 

Thanks Buddy , PCbugfixer. I'm done.
I used system restore now pc working ok. In the end it showed it has renamed some folders of kaspersky .