Maximize application

On one of our machines we use a software program that is written for a
screen resolution 600x480. Now we replaced the monitor which has
800x600 resoltion at a minimum. The software starts and utilises app.
75% of the screen. Question is:

Is there a way to maximise the program or scale it up to fill the
complete screen? I tried some settings in compatibiltiesmode, but did
not work.

Is there a way?

Dirk.

.