I just changed monitors from an HP 19" to an Hitachi CM751 19". Now the fonts are unreadable!

Is there any way to specify the monitor and/or video card from within Knoppix? I have changed most of the screen fonts to Bookman (from the default Helvetica) to make them semi-readable, but why the differences just because I changed monitors?

I am adding screen=1280x1024 at the boot prompt, just as I did previously.

Thanks!