[DustyPorViva]

If open with doesn't appear, then no program is assigned so just go to open and it will pop up asking. The problem(or at least my problem) is with Graal if you have more than one version on your computer, it can't differentiate between the versions, so even if you try to change it to another copy of the exe, it won't really change.

Anyways, open up Windows Explorer.
From the toolbar: tools > folder options : file types
Find nw and delete it. Click new, put in nw, click ok. It should appear at the top of the list now, highlight and then click advanced at the bottom.
In the Action box, put: open. Click ok.
Click browse and find the editor for Graal and then click open.

It should work from there on.