Please Help

Hi guys i'm having a computer problem and am hoping you can help me out.
My C drive (program files etc.) seems to have used up an extra 2GB out of nowhere. It keeps telling me that the My Documents folder is 3.71GB big but when i go in and check its size it's only 336 mb big.
Anyway today i decided to defragment the drive. What happened is i got an error message half way through saying it couldn't defragment some file in a folder that doesn't exist.

"Defragmentation is complete for: (C

Some files on this volume could not be defragmented.
Please check the defragmentation report for the list of these files."

REPORT:

"Volume (C
Volume size = 10.00 GB
Cluster size = 4 KB
Used space = 7.67 GB
Free space = 2.33 GB
Percent free space = 23 %

Volume fragmentation
Total fragmentation = 16 %
File fragmentation = 33 %
Free space fragmentation = 0 %

File fragmentation
Total files = 29,392
Average file size = 365 KB
Total fragmented files = 2
Total excess fragments = 3,682
Average fragments per file = 1.12

Pagefile fragmentation
Pagefile size = 768 MB
Total fragments = 2

Folder fragmentation
Total folders = 3,039
Fragmented folders = 1
Excess folder fragments = 0

Master File Table (MFT) fragmentation
Total MFT size = 47 MB
MFT record count = 32,525
Percent MFT in use = 66 %
Total MFT fragments = 3

--------------------------------------------------------------------------------
Fragments File Size Files that cannot be defragmented
3,682 1.85 GB \Documents and Settings\My Documents\Local Settings\Temp\000004DB"

Could you guys help?