Virus eating my C drive ???

[bondok]

clean up
or formate

[orcutt989]

maybe using a program like treesize professional to see what is taking up the most space could shed some light on what's happening.

http://www.jam-software.com/treesize/

Do what he said. It will tell you the size of every folder on your computer and makes all your directories sortable by size. You will uncover all kinds of large folders you never existed.

Try also using CCleaner. I have run it a couple of times to find that 2GB of space was cleared even after I had just cleaned it a few days before.