can't change screen resolution
i've installed mandrake 9.1 on a thinkpad 390 - very straightforward installation by the way. everything works great so far, except i can't change the screen resolution - i want to increase the screen area. if i go to mandrake control center - hardware - change screen resolution - i have three options, 640x480, 800x600, or 1024x768 (where it is currently set). if i choose one of the other options, it tells me i have to reboot for the changes to take, effect. but after rebooting, the screen looks exactly the same, even though the new settings appear in the control center.
any ideas how to fix this problem?