The virus might leave an finger print (autorun file) in each of the drives. so u are not able to open the drives..
follow the steps to remove it ..............
1. go to 'Run" type "cmd' the Command promt window will open..
2. type "cd\"
3. if C drive ,type " C:
4. type "attrib -r -h -s autorun.inf"
5. del autorun.inf
follow these steps with each drives C,E,D etc.....
than restart the computer , you are done, good luck..