C: Full, deleting doesn't work

I had to convert a video, I already have some experience with 'sony vegas', so I downloaded the trial version of 'sony vegas 10'.
That's when the problem started, I didn't had enough space, so I deleted some programs with 'Ccleaner', but when I looked in downloads, it downloaded 'sony vegas pro 10 trial' two times.
I aborted one of them, and deleted it by selecting it in the downloads folder, then I emptied my recycle bin.
The download stopped, saying that I had not enough space on my C:, which was strange, because I deleted more than enough MB's (more than 'sony vegas 10 trial').
So I deleted some more stuff.
But now I've deleted over 9 GB's of programs/files, the rest of the stuff I all need, but I still somehow have no place on my C drive.

My computer says I have 16.6GB of stuff in my C:/Documents and Settings folder, but in that folder, I have 6 other folders, which together make 7.1GB.
I've made a screenshot of the folders and the amount of bytes they have in them: http://i55.tinypic.com/2n218og.jpg

I hope anybody can help me with this problem, because I have no idea how to fix this myself.