Registry is a place where we can edit all the settings on the system including adding the Administrator Account in the log in page. It is a very important tool to make changes to the system be it XP, Vista or windows7.
Step 1: Open the Group Policy Editor by typing gpedit.msc in the search box or in the Run command
Step 2: It will open the Local Group Policy Editor
Step 3: Expand the User Configuration and Administrative Template
Step 4: Select System and double click on the option prevent access to Registry editing tools
Step 5: It will open a window like this
Step 6: Select Enable option and click on Ok to select disable it.
Step 7: If you want to Enable registry Editor we need to Select Disable option again to re enable it.
This can be used in windows Xp computer as well.