Monitor

Good Morning,
I am running XP Pro. My monitor is AlphaScan 800S and my graphics board is
a Matrix Millennium G400.

I like to run my monitor at a resolution of 480X640. I located a driver on
the manufacturer site and I installed it. I could then change my monitor
resolution to as low as 480X640. However yesterday I needed a smaller
resolution for a given program. I change the resolution to 600Xsomething
and used my program for an hour or so.

When I went back to change my monitor resolution to 480X640 there was no
such capability. I have reinstalled the driver but now I cannot get a
resolution as low as 480Xanything.

Any suggestions on what I did wrong?? Or any suggestions on what I am doing
wrong at the reinstall?? (On the reinstall I do check the boxes that say to
overwrite existing programs.)

Brad