During the past few months, I've added many programs to my Windows XP system. The system registry is getting very large, and I know numerous invalid registry entries exist on my system. The system boots very slowly and I'm aware that a registry with invalid references can cause this type of problem. How can I repair the registry?

I've used several applications to repair invalid references in the registry. You do have to be careful when cleaning up the registry, however. On several occasions, I've damaged a registry by trying to fix it. Before you use any registry cleaner, you'll want to back up the registry—some of these applications even perform an automatic backup for you each day.

The applications that I've used and that I have the most experience with are Symantec's Norton WinDoctor, which is part of Norton Utilities 2002 (I usually install Norton Utilities 2002 as part of Symantec's Norton Systemworks on an XP machine), KsL Software's Registry Healer, and Iolo Technologies' System Mechanic. Of the three, System Mechanic is the most powerful, although I typically use Registry Healer because it's inexpensive and works well.

To use any of these utilities, you simply run the application and let it find the discrepancies in the registry (usually a result of the registry editor comparing entries and scanning the installed software on the system). Registry Healer and System Mechanic use a more automatic approach to fixing the registry than Norton WinDoctor, but all three products basically perform the same steps.