I tried installing Mozilla Firefox and then my computer acted funny. Now I can't open internet explorer or my internet connections on the control panel (to delete temporary files). Nor can I download anything, i.e. Mozilla Firefox or Internet Explorer 8. The whole thing started when I tried signing on to yoville on Facebook and kept getting bumped out saying it could not find a certain location.

Sounds like malware to me. Though, it definitely did not stem from installing Firefox. Download Malwarebytes and run a scan. That should clean off most anything.