1. Repair From Group Policy Editor
a. Go to Run -> gpedit.msc
b. On the left, go to User Configuration -> Administrative Templates -> System.
c. Now in the right pane, select "prevent access to the registry editing tools." It is likely that not configured or authorized. If activated, disable it and if it is not configured, first as you can, apply the settings and then turn it off. More likely, adjustments have been implemented immediately. If not, then run in GPUpdate commands to implement the policy group.
2. Repair by Run Menu
I received this pinch while surfing the internet. Go to Start -> Run, copy and paste the track in the Run box and press OK
Source : http://dhuwuh.blogspot.com/2008/08/registry-editing-has-been-disabled-by.html