Norton Protection, Access Denied : C: PLEASE HELP

When i start my computer, a error message comes up with the title " Norton Protection" and it says Access Denied: C;. I can't open my C drive without freezing the computer. My Anti-Virus is dis-abled, but i can't seem to enable it, even if i right click and choose " Enable Auto-Protect". I've tried booting in safe mode and running all the checks and tests i could, but it doesn't seem to fix the problem when it boots normally. I've run out of ideas, if anyone could help me, i'd be most appreciative.

Thanks,
Kleigh.