Can't make resolution change permanant

[lightbulb]

A friend of mine installed knoppix on an old computer i got. at the time of installation he was using one of his own monitors. when i got the computer back from him and hooked it up to my monitor, the graphics did not show up properly. the screen was fuzzy. i hooked it up to a newer monitor and it worked fine. i changed the resolution to a lower setting and changed to the old monitor without turning the computer off, and the old monitor displayed everything fine. but whenever i log out, the resolution switches back to the default, which is too high.
how do i make the resolution permanantly changed to a lower setting, for both regular, logged-in use, and at the login screen?

[CrashedAgain]

Edit /etc/lilo.conf; add 'screen=800x600' (use your own resolution numbers) to the 'append=' line. Then run lilo to implement your changes. This is equivalent to booting with cheatcode screen=aaaxbbb.

[lightbulb]

how exactly do i edit /etc/lilo.conf, and where do i find it? will i edit it after logging in, or at some point in time during startup? how do i run lilo? is it something like typing "run lilo" or just "lilo" or something else?

[lightbulb]

ok, i read the faq and figured lilo out. (sorry, i was one of those annoying people who asks a question which is obviously answered in the faq)
i did what you said, ran lilo, and rebooted. but it still boots with 1024x760, or something similar. and i want it at 800x600. why wouldn't it be working? is there something else to change as well? would it help if i posted the relevant part of the lilo.conf file?