Display settings

[Nakia L. Jackson]

Hello...

I am a newbie to Linux for sure.  I am running a a PowerMac 466 running 
Mac OS X and Yellow Dog Linux 3.0
I have an Apple Studio display monitor 15".  I was in my display 
control panel, and accidentally switched my screen resolution to a 17" 
Studio Display.
Unfortunately, this has left me with a black screen and unable to  see 
how to make any new changes.  I hooked up a CRT monitor, however, I am 
getting an out of range message.

Is there anyone out there who can guide me through fixing this?

Much appreciated,

Nick