Open With Doesn't Work And Makes Windows Hang

For example when I try to open a .dll file nothing happens. When I right click it, the first option in bold, the default option, is open with. So when i double click that's what I should see, the open with dialogue. What happens is, the window in which the file is located just hangs no matter what i click on it. If I click anywhere outside the window it gets fixed and works normally again, but I still can't get to the open with dialogue because every time I try the same thing happens.

It's also the same if I get to it by right clicking and then selecting it, or if I go to properties to try to choose a default program.

What it feels like is that the dialogue does "open" but it's invisible and doesn't respond to me, since if i click anywhere outside the window that summoned it everything goes back to normal. I'd rather not have to reinstall windows for this.