i tried wAssociate, the main problem is that even though i changed the file association, after the restart of that qq downloader, it auto wipe out the file association again.
The idea is that once you have the "right" file association set you remove from the key the privileges to edit/access the key, leaving access to the key ONLY allowed to a given "named" user account (of course NOT the one you use and you might need to remove also "SYSTEM").
Though everything is possible, I doubt that that program will be able to find and impersonate another user.
Once the program will not be able to write anymore to that key (or wipe it) there are two possibilities:
- this will cause a crash/malfunctioning of the program
- this will be ignored and the program will continue working alright.
What I forgot to mention (my bad, I gave it for already known fact) is that HKEY_Classes_Root doesn't really "exists" , it is an on-the-fly "mirror" of HKEY_LOCAL_MACHINE\SOFTWARE\Classes, you might need to set the permissions there instead.