NTLite - The Ultimate Windows Customization Tool
Autoruns - See what programs are configured to startup automatically when your system boots and you login.
Win Toolkit - BUGS: Do not post bugs in the comments.
CCleaner - CCleaner cleans, speeds up and frees up space on business endpoints.
Ultimate Windows Tweaker - Ultimate Windows Tweaker is a freeware Tweak UI Utility for tweaking and optimizing Windows.
BleachBit - When your computer is getting full, BleachBit quickly frees disk space.