The registry in Microsoft Windows does not repair itself and manually repairing it would take a lot of time. There are software programs designed for the purpose of repairing the registry, however, and they can do it efficiently and accurately in order to keep your computer running smoothly.
Registry cleaners take a certain approach to cleaning your registry:
Registry Back-Up
The registry is very important to your Windows computer. All the locations of files and Windows settings are stored there. You can backup your registry manually by opening regedit.exe and choosing to export a registry copy, but most registry programs do this for you. If the repair should somehow go wrong (if your computer turns off during the process, etc.) there may be problems with the registry and your computer will not work correctly.
Registry Scan
The registry program then scans the registry for inconsistencies. There may be links that are broken or keys that are no longer in use that are slowing your computer down. This usually takes a minute or two or less.
A report on the scan is then displayed and you can choose what to repair or delete.
Repair the Registry
A good registry optimizer won't make too many mistakes, so if you don't know much about the registry it usually won't hurt to go ahead and fix all the problems. Select them all and the software does this all automatically to optimize your registry.
Once the repair process is finished, your computer will be optimized and any registry problems that were bogging your computer down will be fixed. You just need a good registry cleaner to see how much more speed your computer can have.