Hello Sean, Link Removed to Windows 7 Forums
You can do a "System Restore" to undo the change you've made.
To access "System Restore" open Control Panel, click on "System and Security" then click on "System" in the left pane under Control Panel Home click on "System Protection" which will open your "System Properties" window, then click on the button "System Restore" it should open so you can choose a Restore Point.
Make sure you have no other open programs or windows as it will restart to perform the necessary actions, so let it run it's course.
Let us know how it goes
Don