My parent's computer was working fine until today, when it was started up and was in a strange video mode. I checked that it was not in safe mode, then checked the display properties to see that the res was stuck in 800x600 and 4-bit color.

I tried knoppix on the computer, and it worked fine except for a message saying "undefined mode: please select video mode" where i selected 0 (first one) and it worked fine.

I checked the drivers, and the ones for the monitor and display adapter were the latest ones (nothing changed from yesterday)

anyone have an idea how to change the resolution back?

Any changes? (software or hardware). If not...

First, try System Restore from the last good checkpoint.

If that does not work, I would completely uninstall and then reinstall the drivers.

I tried system restore just then, but nothing happened.

I dont use the computer so i dont know excactly what happened, but my mom said she just shut the computer down as usual and it started up like so. I reloaded the driver for the display adapter, with no change either.

we didn't make any change to the computer.

Could you post manufacturer and specs on the computer? 4-bit color is quite unusual, the smallest that I am acquainted with is 8 or 16 bit!

Is the video integrated on the board, or do you have a separate video card-you don't exactly say. If you have a separate V.card, please post the manufacture, model and specs on it.

Why did you use Knoppix? Are you unable to boot the system?

When you Right click on the desktop/Properties/Settings, what options are you given in the selection boxes?

the computer is pretty old, about 4-5 years. Its an eMachines t1801.
800mhz celeron
320 MB ram (from 128)
160gb hd (from 20)

it has onboard graphics, more specifically an intel 81810.

Windows does work, but only in 800x600 and 4-bit. I tried knoppix to see if it was a hardware or software problem, but only saw a message saying "undefined video mode" and from there knoppix worked correctly(resolution-wise)

When i do desktop properties>settings, the only options are 4-bit(lowest) for color quality and 800x600 for resolution

One last suggestion since you have onboard graphics; find the Mainboard Drivers and reinstall them. They should contain the video drivers, since you have integrated video on your mainboard. They should be on a CD that came with the computer. They may be labeled Mainboard Drivers, Chipset Drivers, Computer system, or something similar. If your folks still have their manual that came with the computer it may give you a clue.

If that doesn't work, you can try to replace the CMOS battery. There is a far out possibility that the CMOS is not holding it's settings because the battery is dead and it is defaulting back to factory settings. Battery only costs a couple of bucks at any drug or camera store, just get the right one.

If still no joy, the only thing I can think of is it's time for a new computer.