When you right-click a file and choose “Open With“, and click the “Choose Program…” option, the list of registered applications are displayed in the Open With dialogue. Programs that are not already listed in the Open With dialogue can be added manually using the “Browse…” option.
However, in some cases, I find that when you browse to locate an application, it does not get added to the Open With dialogue.
This happened to me earlier after updating an application – the files normally associated with it weren’t, and I couldn’t get them to. However, a quick search on Google found an excellent, portable application for forcing program to be registered. Named “OpenWithAdd“, it works quickly and simply – launch a .exe and in the resultant Window, select the program you wish to add to the Open With dialogue. And that’s it. And in my case it worked a dream.