re: A few suggestions
1. Defrag your hard drive.
2. Download and install a firewall, use it to identify obscure applications accessing the net, for example an application named "C://Windows/HWC32.exe". Delete them.
3. Download and install "Spybot Search & Destroy", use it to immunize your computer.
4. Don't reinstall everything, you could re-instate alot of spyware that you had previously deleted.