How do you change default program for file types to nothing?

I accidentally changed a file type to open with Adobe Reader and now I want to change it back to how it was. Nothing. The file originally was nothing, now I want to change it back to nothing.



I want to know how to fix this using Vista.How do you change default program for file types to nothing?
do it from dos, use rename cmd, search it also here http://www.Wattsaver.euHow do you change default program for file types to nothing?
You can't do it in Vista using the normal interface, you need to edit the registry.



Press start, and type in 'regedit'. Press enter.



Navigate to the following location:

HKEY_CURRENT_USER %26gt; Software %26gt; Microsoft %26gt; Windows %26gt; CurrentVersion %26gt; FileExts %26gt; (your file extension) %26gt; OpenWithList



Delete the 'a' on the right-hand side. It should be listing the path to Adobe Reader. Once it's gone and you've restarted your computer, the file should have no default program again.