You sure the key is working correctly in other apps? (had to ask)
Im not familiar with that keyboard. But maybe possibly the cap lock key is making it not function on your particular keyboard.
Try other keys also. And maybe give your "Fallout_default.ini" inside your Fallout 3 folder a look.
Scroll down about half way , find [Interface] and then look at this line >>> bAllowConsole=1
I think that might be the line for it ? Just a curious check to see if that might be screwed up.
Well beyond that , if you havent been here >>> http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01853744&cc=us&dlc=en&lc=en&product=4007375&submit=
Try that.