[SOLVED] Need to un-associate a file type from a program

So, I have this file that I need to be compatible with something, it's a compressed file and the actual files inside are compatible, but I need it to register as a certain file type instead of what it is (an archive with an arbitrary filetype stamped on there by whoever made it, like, for example, .001 or something like that). Well, problem is, I already opened it as an archive and now I can't change the file type (yes, I know what I'm doing there, I've done it hundreds of times and it hasn't broken anything) without extracting and recompressing it. I don't want to do that, so how do I get windows to associate it with absolutely nothing again? No, it isn't an option from the archive program itself since it isn't a standard filetype.

Generally .001 should be associated to Winzip or other zip utility but if you want to disable that go to Control Panel\Default Programs select "Associate a file type with a specific program". Select 001 and click Change. Then choose browse other and select a new program for the association.

To actually remove all associations you would likely need to edit the registry manually.

Edit: Nevermind. Apparently 7-Zip can still do it if I'm outside the archive.

Just FYI ...
You would have to look under each user (where user is something like S-1-15...) in HKEY_USERS\each-user\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.001\OpenWithList and delete all but the (Default) entry.
... then logoff & log back on.