Hi hefs, this is going to sound really...wierd...but it is worth a try.
Unplug the extra keyboard from the laptop, and while the laptop is on...open Notepad, and then mash all the keys together

From what you've described, it sounds like a couple of the buttons might be jammed...
If you find that you can type normally with the keyboard unplugged, plug it back in and mash those keys
I've seen this a few times, and a mash of the keys normally works fine. But it could be something more sinister as well (but what - i don't know).