The instructions you were given should have told you where to find the relevent entry.
You will have noticed that you are faced with a few major directories. These will all open out and unless you have some idea where you are going it really will be like looking for a 'needle in a haystack'
Try clicking on HKEY_Local_Machine then Software.
Before you do this, however, I would recommend you create a Restore Point or some other form of Registry Back up.