When you say "Reboot" do you just mean Restart the computer, as that's what Reboot means, or do you mean Reinstall Windows? If you want to Reinstall Windows you are probably going to have your Schools IT dept to do it for you as they have certain files, and network protocols installed on your computer.
As for running horribly here is a few things you can do:
1.Go to Add Remove Programs and remove any programs you do not use.
2. Download CCleaner
and delete temp files, run registry cleaner too.
3. Turn Off System Restore
4. Update Virus Definitions for your AV software and run full scan.
and run full scan
6. Defrag computer.
7. go to Crucial.com
and run the free scan. This will tell you how much RAM you have and your update options.