CCleaner is a freeware system optimization and privacy tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space.

Running this can find some very strange things. I found file extensions (which should be typically .com .exe .html) as complete sentences of meaningfull text. Either this was random registry corruption, or software installations gone bad.

Ended up removing 238 meg of assorted junk.