Well, we can't look at your machine, so we don't know the answer. All we can do is tell you how to find out:
1. Delete all but the latest system restore point from the disk cleanup wizard (advanced).
2. Download Treesize Free from http://www.jam-software.com/freeware/ and start analysing the contents.
I bought an ASUS EEE 1000 (no h) from craigslist a few days ago. When I got it only has 7.48 gb on the c: drive and almost all of that is already being used. I took it to a tech he found a partition under disk management and told me that there is 7 more gigs not being used and created an icon for me under "my computer". However moving things over there is not really freeing up much space. I am running Windows XP.
I have done the disk clean up. Nothing...
Where is all this space being used. I mean under add/remove programs it's just got the main stuff to run the pc. No extras at all. Any advice would help. Thanks.