Hi guys.
I recently downloaded a free version of Corel Snapfire to see what it is like. Not overly impressed, I decided not to bother using it but found that it had installed itself as my default picture viewer. A few days ago I found out how to change the default viewer back to windows picture & fax viewer via control panel/folder options in our admin account. No problem I thought.... Anyway I've just been trying to alter the background picture displayed on our youngest's user account and found that Corel is still showing as its default software

I tried to change it in the same way via his account's control panel but when I select JPEG and JPG in the file types tab, the 'opens with/change' option remains hidden and won't work. I'm presuming this is to do with the fact that I'm trying to do something the user account hasn't got permission to do but I can find no way of change the account's default viewer settings via the control panel in our admin account. Can anyone assist please?
Cheers!