that Disk Cleanup should be located in your %SystemRoot%\System32\cleanmgr.exe,
EG if you're using Win XP it will be in Windows/System32.
If you right click the shortcut in the Start > Programs > Accessories > System Tools, does it give the same directory path?
If not, then perhaps it got moved somehow, and the shortcut changed as well. Unlikely I know, but that's all I can think of.
When I try to run Disk Cleanup from the Drive Properties, I get a pop-up... " Windows cannot locate the Disk Cleanup program. The program file may be corrupted or may have been deleted from your computer. To reinstall Disk Cleanup, run Windows Setup again."
Incidently, I can run Disk Cleanup from System Tools in Programs/Accessories.
I don't find anything in Windows Setup to reinstall the Disk Cleanup.
Any ideas about the problem and solution thereof? Thanks.