weird monitor problems

I have a monitor that is very unusual, and has had the same problems
since my brother got it 5 years ago. The monitor in question is a KDS
17" VS-7I. It has the pickiest supported resolutions I've ever seen.

In windows, the display depending on resolution will only fit properly
if the monitor uses a specific refresh rate. For example 1024x768 needs
to be at 85 for the horizontal frequency to be at 68 or so.. Anything
else and the horizontal frequency will be too large, the sides of the
picture will be squished together, and impossible to fit correctly on
the screen. This is the same with every resolution. Locking the
resolutions at the correct frequency is the easy solution for windows.

HOWEVER, whenever the computer is in non windows mode. For example, at
bootup, or in dos, the monitor uses a 720x400 resolution with a
horizontal frequency of 34. Thus it only covers half the monitor, in
the center. Is there anyway to fix this?