P2P is Peer-to-peer. It refers to programs like eMule, Kaaza, etc. I don't think that's your problem.
Do the following: click Start, select "Run...", type "sfc /scannow", click OK, and let the process finish. After the process has finished and you have handled any dialog boxes that popup from the scan, check IE and see if it works better.
If IE still seems slow, use
this guide to clean up and optimize the system.