how do I just completely erase everything and break it down to the original necessary basics?
You could Format your computer and re-install everything.

But before you do something drastic like that.

Try these steps :

1. Scan your computer too see if you got any viruses.
2. Scan your computer for spyware and see if you got any on your computer.
3. Back-up any important files that you want to keep. That's if you decide to Format your computer.
4. Download HijackThis if you dont already have it and and copy-and-paste the log file here.
5. Un-install any programs that you dont use often. Why have something take up space when you dont even use it ???

How about giving one of the Linux distros a try ??