So I'm pretty sure I have some kind of virus on my laptop. My CPU usage is always at 100%, everything runs incredibly slow, etc. I've been running a ClamWin scan for 24hrs and 30 minutes, it still hasn't found anything and is STILL scanning. Any tips on what I should do?

Presuming you're not on Win9x, open Task Manager (Ctrl-Alt-Delete, then hit the Task Manager button), have a look in the list of processes and see which one is using your CPU time.
Try to kill that process, then run a virus scan.

As long as the process is taking all the cpu, it's pretty normal that all other processes are extremely slow.