You need to backup your Windows registry file before editing.
Solution
1. Go to Start > Run. Type Regedit and press Enter.
2. As an example, you want backup HKEY_CURRENT_CONFIG. Right click on HKEY_CURRENT_CONFIG and choose Export. It will prompt you a pop up box to save the file anywhere on your desktop/laptop. If you just want to edit some specific registry file, you can just right click on the registry file and export. The steps will be the same for all.
3. To import (restore) back, go to File > Import. Point to the file where you saved on step 2. The registry will restore back to the previous version.
