I’ve been cleaning up people’s PCs’ during the last few days.  I thought I would share some of the secret handy sites (courtesy of Bitchin Bob):

ophcrack
Download the appropriate CD IMAGE (.iso file) for your operating system. Boot to the CD and find all your computer’s passwords.
http://ophcrack.sourceforge.net/download.php

nirsoft.net
Tons of utilities to investigate your computer’s operation and performance.
http://nirsoft.net/panel/

Windows Live Sysinternals
My favorite app here is autoruns. It shows you all the stuff that runs in the background on your computer and gives you the ability to disable it or delete it. There are many other nifty apps here too (like process explorer).
http://live.sysinternals.com/