Shortcut Keys Mysteriously Get Disabled

I was just wondering if any of you other coders have run into this. Most of the time my VBA editor works just great but there are intermittent times when my F8 (step into) debugging key doesn't work. Sometimes it does, sometimes it doesn't and there doesn't seem to be any pattern. The debugging toolbar button does work when the F8 shortcut key doesn't.

But that's not all, as they say. Even my ctrl+C and ctrl+V (copy and past shortcuts) won't work at times as well.

I've look around on the web for solutions, but I don't see anyone experiencing exactly the same thing I'm experiencing.

Any ideas?