Safari Resets itself

I wont bore you with the details, a synopsis:

1. Safari works fine..happy with it in fact
2. Idiot me installs McAfee plug-in (site advisor)
3. Deleted McAfee plug-in
4. Safari keeps re-setting itself making life tedious (unchecking java and all other nonsense)
5. Safari works terrible so had to install Firefox

I like Safari, want to fix safari. HOW IN THE HECK do you re-install/fix it???