Freeware: Regclean

Microsoft RegClean v4.1a build 7364.1\fixes any errors you may have in your Windows Registry. The Registry is the central database for Windows. When you install, uninstall, and reinstall programs on your computer, Registry keys are created, modified, and deleted.

Eusing Free Registry Cleaner 1.6Eusing Free Registry Cleaner is a free registry repair software that allows you to safely clean and repair registry problems with a few simple mouse clicks.You can restore any changes made using the software by choosing Restore registry backup.

Free Registry Cleaner for Windows 7 1.0.0Free Registry Cleaner for Windows 7 is a free, Windows 7 compatible utility that scan and clean up registry problems from your computer. Registry errors occur for many reasons, including references left behind after uninstallation.