Problem to stetch the display

I have a 1024 x 768 display and when I chose 640 x 4__ the scren get small and and doesn`t strech out itself. In some program u have to run in 640x480 or less, and when I have this problem. The window picture when I start is also small becase of this, so plz hlp me!!!!! :eek:

Did you check the Refresh Rate when working at 640x480?

...It was much easyer than I thought, just press Fn,F7 (Font) on my computer...