The "Registry Cleaner" program, is a add-on in ItweakU. It installs automatically when you install ItweakU Professional. How to use this program:
Start Clean Registry from the menu File -> Registry Cleaner. When you have started the program, you will see a lot of lines with program names. This program helps you remove entries from programs you already have uninstalled. Use this program directly after you have uninstalled a program, then look for lines from that program they should have the same name as the uninstalled program. If you see a line like that, select it and hit the delete button. The entry will be removed from the registry. NOTE: If you are uncertain about a line, then just leave it be, it's better to be on the safe side than removing a line that a program uses.