Hi, I just purchsed an LCD monitor and hooked it up to my computer which has Fedora Core 3. Since I changed my monitor size from 17" to 20", I tried to change the resolution; however, I accidentally configured with wrong resolution, and now when I restarted the computer, it does not display anything at all.

The machine starts up normally, goes through BIOS and it begins to start all the services. I see many [OK]s when the OS is starting up the services, then once the startup process switches to GUI, the screen becomes blank (black) and nothing happens. The computer even does not complete the start up process, I believe.

I am guessing that I need to change the configuration saved in /etc/x11/xorg.conf to correct setting, but I cannot do it because the monitor does not display anything, and because the machine won't complete the boot process.

Could anybody help me resolving this issue? How can I start up the machine even in a CLI mode so that I can access to the xorg.conf file? Can I boot the computer from the Installer CD to modify the xorg.conf file?

I don't know the exact details for Fedora, but yes, booting from CD is what you'll need to do. The installation CDs might have a 'rescue' mode that you can use to boot the computer to a console. The next step is to mount your hard drive so that you can access the files in /etc, then do one of two things. You can either change /etc/X11/xorg.conf to take care of the resolution problem, or change /etc/inittab so that it doesn't boot straight into X (the GUI) when you reboot.

I'd recommend finding the line in /etc/inittab that looks something like:
And change the 4 to a 3. That will make the machine just boot to a command console on reboot. You can then try different xorg.conf setups, and if it doesn't work, it will either drop you back to the console with an error, or you can kill X with [ctl]-[alt]-[backspace] if it locks up on you.

That's the general idea - someone with Fedora experience could give you better details if you need the actual commands to get into rescue mode and mount your drive.

In your GRUB prompt should be "failsafe" or "single" mode. Try it.

Thank you both of you. Using the Install CD let me start up the machine in rescue mode. Now I can see both CLI and GUI on my screen.