There is no scandisk utility. Microsoft went back to Checkdisk (XP requires unfettered access to all files before running a disk utility, so scandisk which ran from within the gui was replaced by the old checkdisk which runs from outside the gui). Double-Click on My Computer, right click on a drive, select Properties and the Tools.
Disk Cleanup looks for files that can be eliminated or compressed. It is not as comprehensive as 3rd party utilities such as Clean Sweep (part of Norton System Works) but it's okay.