When I check the properties of my C drive I see I have used roughly 11.0 Gig. However when I open the drive and 'add up' the sizes of the files there (from windows to my documents etc) I only get 4.0 Gig in use. The other 7.0 is apparently missing. When I search my system for large files I find nothing. Is this normal or do I have a big file hiding somewhere?