Problem or virus on disk C

Hello,

I hav a problem opening my local disk C. i think it has a virus on it. i can't open disk C juz normally. if double click on disk C, it nvr open and it show one box which shows open with ...................... i hav a symantec antivirus but it can't delete or find any virus when i scan. plz help to find out what is the problem and tell me how to solve it.
thz u vry much in advance