A few things can be going on 1) There could be something hidden going on or 2) could be where the Pagefile is being used.
1) XP Click on Tool, Folder Options - Vista and Up click on Organize and then Folder Options
Click on View tab and then click on Show Hidden Files and Also uncheck Hide Protected Operating System Files. Then ok out of the box and see if there is anything else on it?
2) Right Click on Computer
XP - Click ON Advanced Settings Tab -- Vista and Up click on Advanced System settings Link on Left side of System Menu.
Click on Settings for Performance then click on Advanced Tab - and then Click the Change Button for Virtual memory
See if the drive (D: drive) has a pagefile set to it. If it does click on the drive and then click on No Page Filing. If there is no other drive with a Page File then select another drive (Like C) and then set it to System Manager Size.
If a check box for "Automatically manager paging file size for all drives" is check at the top uncheck it and follow previous instructions.
I switched the pc off and the day after i turned it on and it was empty. It seems it is now fixed
Any idea what caused that ?