I had to do the exact same thing once, you need to edit the registry.
Someone showed me how but now I can't remember.

If you need a utility to do it,

Go here
http://hotfiles.zdnet.com/cgi-bin/texis/swlib/hotfiles/search.html
<http://hotfiles.zdnet.com/cgi-bin/texis/swlib/hotfiles/search.html>

and search for "registry"

good luck,
Jack

                -----Original Message-----
                From:   Wolfe, Robert [mailto:[log in to unmask]]
                Sent:   Wednesday, March 29, 2000 8:43 AM
                Subject:        Change Associated Files in NT4 SP6a

                Need a little help.
                I have accidently set up an association for files with the
.hgl extension
                for a program AutoView.
                If I go to My Computer/View/Options/File Types you can
supposedly change
                this. However once there, there is no listing
                for the .hgl If you delete or Edit any of  the Autoview info
you end up
                having to reinstall Autoview. If you try and make a new
association with
                .hgl it tells you already in use as hgl_auto_file yet that
is not listed in
                the files types either to be able to edit.
                Our MIS group had no answers either. All I want is to be
able to undo the
                association of only the .hgl file type
                with any program and can' t seem to get there form here.
                TIA
                Bob
                Executone Inter-Tel Business Information Systems, Inc.
                Robert M. Wolfe C.I.D.
                Lead PCB Designer
                478 Wheelers Farms Road
                Milford, CT 06460
                Phone: 203-882-6405
                Fax:   203-882-2727
                Email: [log in to unmask]