Where is the " Clean up System Files" in "Disk Cleanup Wizard"?
It already shows you all options to clean system files (system service pack cleanup and the dialog more options are a system task).
Running it as normal user doesn't show it and shwos the button:
This happens if you run %windir%\system32\cleanmgr.exe always as admin or disabled the UAC completely, here cleanmgr.exe always runs as admin.