What resolution are you currently running?
I'm assuming you're using a PC and not a Mac... If you're using Windows XP, go to your desktop and right click in the empty space. Select "properties" and try to find out what resolution you're using. If you're using Vista or Windows 7, right click in the empty space and click on "screen resolution".
What resolution is set? If it is 1024x768, can you slide it over to make the resolution bigger?