I recently purchased a Dell Inspiron 15r. It is pretty good for gaming, however I have recently had a problem with running certain games in fullscreen mode. Basically, they don't change the screen resolution, so my games are the same size as they would be in windowed mode with large black borders filling the rest of the screen.
This didn't start happening until Viriax crashed while in fullscreen. It didn't change the resolution back to normal, and it was so blown up that I had to fix the resolution from the command prompt using QRes, an open source program for changing the resolution from the command prompt.
So far, this has happened to three of the five games that I've tried to run in fullscreen, with the games that worked normally being Osmos and Machinarium, and the games that had the problem being World of Goo, the original Starcraft, and the aforementioned Viriax.