I was trying to remove a virus and foolishly did not backup registry keys I deleted because I (thought) I only deleted entries from the folders of programs I did not care about. However, I think I have done something wrong here:

Now when I open a context menu (right click) in any location and hover over the "New..." option I don't get any options. It has a greyed out box saying "(Empty)".

So far I have found out the the entries themselves are still there (using the locations provided here: Windows 7 - Add an item to 'new' context menu). I have also used a program recommended in that thread which also finds the entries intact and enabled.

So it seems maybe I have deleted the entry which tells Vista where to look to find the files that can be created.

How can I restore this so entries are shown again? I know system restore is an option but as I have said I did this when removing a (very stubborn) virus so that is the last resort.