Hi....on one of my computers I am losing hard drive space rapdily.  The C: drive is part of a PARTITION and although its formatted size is around 9 GB ....when viewing the drive in explorer and using Properties function for all hidden and viewable files it only comes in at  around 5.5 GB.  I have no idea where the other 4 GB APRROX. is gone?  I assume it's a virus and have used Hijjack This, McAfee and several adware/spyware programs to fully scan drive in safe mode but I can't find anything abnormal to attribute to the 4+BG of spave gone.

Running Windows XP SP1

Any help would be appreciated.  THanx JasonPrograms might be creating temporary files and placing them on the C: partition.If it's SHOWING 5.5 Gbs, why do you think it's using 9 Gbs?Check your page file, or do a search for large files and see what it might be. If you see that you have a 4GB history file then you know what happened."Run Disk Cleanup and remove all but the last restore POINT. See if your System Restore cache and Recycle Bin size is set at a reasonable level (Say 1024Mb) on each drive, and reduce the IE Temporary Internet Files cache and History cache to the minimum. Install CCLeaner and clean out all of the junk files. Unhide all files and folders and remove the hotfix uninstallers ( $NTUninstaller$ ) from the hidden C:\Windows folder and remove their entries from Add-Remove programs.
(Note: Some Security updates should NOT be removed so check in add-remove programs - before - doing this TASK.)
Then remove the contents of:

The C:\WINDOWS\Downloaded Installations folder
The C: WINDOWS\SoftwareDistribution\Download folder
The C:\WINDOWS\Temp folder
The C:\Windows\pchealth\helpctr\Datacoll folder, and...
The C:\Windows\Prefetch folder

(You can add these folders to EmpTemp if you have this program installed.) Then run chkdsk and defrag."

EmpTemp & CCLeaner File Cleaner

To make your shutdown work cleanly install the... User Profile Hive Cleanup Service

TweakUI is useful to have on your system for certain repairs... Powertoys/TweakUI

ERUNT-NTREGOPT