Resolution problem on startup

[jetztsofort]

Hey guys,

I'm completing my now working Mac OS 10.4.8, but it happend a little accident: I've got two monitors (20" about DVI, 19" about VGA). It worked only one screen, the 19", so I installed the nVidia-Package. All worked, I restarted, and I could change the resolution. But in this moment, I clicked accidentally on a not working resolution, so I got a screen by coloured lines and nothing was readable. I restarted the PC, but Tiger has saved the settings, so I don't know, how to change them again!? I tried with "Graphics Mode"="1024x768x32", but it doesn't change anything. On boot-up the white screen with the Apple logo appears on both screens, but on login it shows in the 20" a small grey square and the 19" shows for a few seconds the login normally, but then appear the coloured lines again.

Can you please help me in this situation?

Many greetings,

Chris