As WTP stated - mine is also around the same size - by chance are you doing local backups to your system drive?
I have 699mb left of 89.7gb left on (C) 52kb left on 18.9 gb (D) recovery and 2.34mb of 2.88gb on HP tools (E)
Deleted most files and photo's-cleaned up and defragged several times
Chatted with Norton and they said Norton equals about 6gb last nite...Norton says its a microsoft issue
still using Windows 7 Home edition because I like it
Mine backs up to local. I copy it to an external drive; just haven't bothered to change it to back up directly to the other drive. Soon.
Anyway. Open My Computer and click on your C:\ drive to open it up. If you're saving locally, you'll see a folder named N360_BACKUP.
Also, how big is this file? Mine has gotten huge. 107 gb! Maybe that's part of the problem.