Hi i have a Dell Laptop and when i bought it windows 2000 was installed on it.
Then when XP came out i installed that on my Laptop. Then after a few months the Laptop would only uses half of the screen and not the full screen.
Wow, never heard of that before but give this a try. Right click somewhere on your desktop, and click properties, then look for the tab that says settings. Try fixing the resolution. Push the bar as far it will go, then hit apply and ok. G'luck man.
Theres one of Three things you can do, Makes sure you have the video drivers installed and the resolution upped. You can Try pressing the Fn F7 key to stretch the video and last but not least if none of the others work, go into the bios and make sure that video stretch is enabled. The FN thing will work for sure. I work with dell laptops constently.