CCleaner is a free Windows utility that works on both Windows Vista and Windows XP. It does only a few things, but it does them very, very well, including file and object cleanup (I seldom run the program without it cleaning up at least 300 MB of stuff from my system/boot drive, often more), as well as Registry cleanup (it usually finds at least half-a-dozen items it can clear out on my behalf). These functions come from the built-in Cleaner and Registry tools shown at the upper-left quadrant in this screenshot.

The Cleaner tool is well-versed in the kinds of files that Windows leaves laying around in its wake, including various types of IE files

• Temporary Internet files, which include markup and graphics for Web pages you’ve viewed recently
• Cookies, or the invisible but often important text data that Web sites like to record and store about themselves
• History, or the URLs you’ve visited recently
• Index.dat file (which indexes all the other zillions of files that IE uses, and can grow very large over time; MS says you can’t delete it, but this tool cheerfully manages to do so anyway)

It also deals with various Windows Explorer data files, including:

• Items from the Recent Documents list
• Run command recent arguments
• Autocomplete text
• Various other lists of most recently used objects and elements (MRUs, as they appear in the tool text above)

Finally, the Cleaner tool also clears out numerous system files and objects, including

• Recycle bin contents
• Temporary files of many kinds, including .tmp files and others
• Clipboard contents
• Memory dumps (created any time Windows crashes and writes a .dmp file)
• Chkdsk disk fragments (unusable file chunks that Chkdsk finds and saves for later inspection)
• All kinds of Windows log files