I need help. When i have a window for a game open on my computer, it is smaller size than on other comp. I have a large flat screen. How can i change the settings for the size?

It will be helpful if you can tell us as much about your problem as possible.

what sort of computer do you have? (Mac/PC)?
What operating system? (WinXP/MacOSX/Linux/Win9*/WinME etc)
What screen? (dimensions in pixel)
What game?

At the moment, it's hard to say what the problem is.

however, you can try hitting Alt+Enter to switch between Full screen and windowed (works for some game and DOS boxes)

Sorry for the lack of info.
Its a packard bell,windows xp. The games are msn online games

right click on the desktop, select 'properties', click the settings tab, and drag the resolution slider down a notch.

then click 'apply'.