Resolved Disk c not showing real free space amount

I use Windows XP professional SP3 with a 500 GB Hard disk partitioned as
C (300 GB0 and D ((200 GB).

Yesterday I went to C properties to do a disk cleanup (after cleaning all temps, defragging etc...) and to my surprise disk C shows an incredible
80 GB used space when in fact it should be only 13 GB as I have always noticed. Disk D shows the correct amount of used space as 11 GB.

I recently deleted like 8 movie copies (each 4.7 GB) from my hard disk (they are too large to go to the Recycle bin so they are erased on the spot).

I have not installed any software in the past month (all softwares that I have installed are on partition D) so I only have the system files on C and 2 or 3 applications totalling about 13 GB.

I don't know why windows explorer shows 80 GB on C and I am looking for help to fix it. I googled the issue but only found related issues from years
2000 thru 2008 giving different solutions (but the issues weren't exactly like the one I am experiencing althought they were all related to windows not showing the correct amount of disk space.

I have searched for files larger than 1 GB with no results, none of my docs, pics, videos exceed a few MB. I need help to fix this.
Thanks

 

Try using TreeSize Free to see what is using the space. Their online manual is under Help & FAQ.

 

Thanks for the help. someone suggested me at another forum to download TreeSizeFree and I could see instantly on the list that Drive "C" had 80 GB and when I opened C to see the files I saw a .dat file (64 GB) from Diskeeper (the automatic defragmenter that I have used for years and the best in the world at it).

I was very surprised as to the size of that .dat file , this is the first time I see a .dat file of more than some MB but this one was huge at 64GB and I don't know what data contained and how it was created (Diskeeper never created a .dat file of this size) but any way I deleted that file right on the spot and inmediately the C size came down to 16 GB
(the normal size I have had for long)

Problem solved !!! thanks to you, you gave me the correct application to use to find the culprit Now I am going to contact Diskeeper about this to see if they can provide explanation.