If you know the virus name. Boot up in safe mode then go to your command prompt.
use the cd command to go to the folder where the virus is located.
cd \windows\system32
unhide the virus
attrib -r -s -h virusname.exe
delete the virus
del virusname.exe
If you don't know the virus name then you will have to do it via a software approach.
Thats my limited knowledge but i hope it helps you out