1. Download registry-cleaning software. Several free registry-cleaning software products with good reviews are available on the software review site CNET, including Registry Cleaner and RegToy. Once you have downloaded the program, double-click the 'start-up.exe' or 'setup.exe' file and follow the on-screen instructions to install the program onto your computer.
2. Open the registry-cleaning software. The main screen has several options, including 'Scan.' Depending on the software you have chosen, you may be given a choice between several different system scans. Choose the 'Full scan' to check every folder in your registry for bad files.

3. Click on the 'Start Scan' or 'Scan Now' button. The registry-cleaning software begins scanning the registry. A progress bar monitors the progress of the scan and, as the software finds corrupted or unnecessary files, it lists those files by name.
4. Press 'Next' or 'Continue' once the scan is complete. Most registry-cleaning software provides a detailed report when it has finished scanning the system. This report lists all the bad files found in your system's registry and recommends fixing those files. By pressing 'Next' or 'Continue' you are taken to the screen where you can either delete or restore the files.
5. Delete the files from your system. While registry-cleaning software usually includes a restoration option, which directs the software to attempt to fix any corrupted files, in most cases the corrupted files on your system are not essential to the running of applications and programs. If you do not recognize any program names in the files that the registry-cleaning software has found, it is more than likely safe to delete them. Deleting bad files from your registry has a more pronounced effect on the operation of your system than restoring the files.