Laptop monitor in wrong aspect ratio

I recently wiped my hard drive and reinstalled Windows. I'm in the middle of reinstalling my Dell drivers (not going exceedingly well, but that's a separate issue) onto my Inspiron E1505. For some reason, the picture on my 15.4 monitor is streched horizontal and when I go to Display Properties -> Settings, my previous resolution of 1200 x 800 is unavailible. I only have the choice of 800 x 600 or 1024 x 768. How do I make Windows recognize I have a widescreen monitor?

This is not an external monitor, it's the one physically attached to my laptop that folds the notebook closed.