You still have not given me any basics of what PC you are using or, more importantly, the operating system.
You will have to be quick, but try ...
1. Click on Start, Run
2. Type in CMD and press ENTER
3. Type in the following command ... shutdown -a ... and press Enter
If you can stop it shutting down, go to ...
http://www.kaspersky.com/virusscanner
... or you could try a sasser clean-up utility such as
Stinger and
Read This also.
Another alternative is to 'slave' that drive off a well protected PC and clean it up.
Bottom line, reformat.