To get the maximum life out of your Windows XP operating system, you will need to run a periodic diagnostic check against the Windows Registry and repair any errors when and if they are found.
Your best bet would be to actually schedule a registry scan to run once per week or perhaps even every time you restart your computer.
But why is repairing your registry vital to your PC's health? Here are 5 reasons:

1. If you install a software program and then later uninstall it, remnants of the old installation are not always cleanly removed from the registry.
   
2. If you attach a USB device to your PC and then remove it, or install a piece of hardware and then later remove it, information about that hardware device will remain in the registry.
   
3. If items are not cleanly removed from the registry, then referential integrity errors can creep up, due to invalid or obsolete references.
   
4. The larger your registry it, the longer time it can take for the operating system or your applications to traverse the registry and find the information it is looking for.
   If that occurs, your operating system can slow down, freeze up, and even crash.
   
5. Errors in your registry can also cause your applications to become unstable, to freeze up and hang, or even crash, if information that is being searched for is not found.
   

How common are registry errors? Unfortunately, they are more common than you think! But when you run a Windows registry repair utility, you can typically experience a noticeable performance improvement immediately.