Can I make windows7 run full page in virtual box

I have installed Windows7 on a virtual box but am unable to make it fill the page. I want to run "Betangel Pro" but not enough of the page is visible, just a small widow about one third of the total desktop.
I have tried maximising the Virtual box window which does then fill the desktop,however, the same does not happen with the program I am trying to run.
I have tried running the program in Wine but it will not run at all.
Help!!!!!, Stan