I have Fedora Core 4 and it has been running fine. I decided to increase the screen resolution through the display option in Gnome. It told me to reboot and now I seem to be in a "catch 22"...

At some point during rebooting, the SyncMaster pops up a floating box saying "not optimal screen resolution" and won't allow me to see the screen. Linux may very well have finished the rebooting but I can't see a thing.

I guess my question is, how do I change my resolution back to something acceptable during booting?

do you have sshd (or similar) set to start at boot? if so, you can ssh into the box from another computer and change your settings back to the way they were.

if you dont have sshd or telnet use the fedora emergecny cd or the grub boot control to access the filesystem as root and go to your xorg.conf file and chnage it back, there should be a backup in the dir with xorg.conf that has the old setings. messing with res`s is hard and you should keep a fresh stable copy of xorg.conf around jsut in case, i put mine on my USB key jsut in case.

I investigated grub but have to admit I don't know to proceed.

I got as far as stopping the booting process ( I have a dual-boot set up ). It gives me options to e edit, a append, etc.

hum, i dont recall the command in grub to access repair features, and i am presntly not able to test, lets say google that one.

but if you can use a repair disk like FC4 5th disk, the repair disk. i am looking into the grub thng now, one sec lol

another good idea is there arew ALLOT of bootdisk out there for linux, find one that can mount / and use it to naviagte to /etc/xorg.conf or something like it and do the repairs there.

I'm breaking out FC4 5 now.

FC4 Disc 1 will have the rescue console on it as well. Insert the cd, and when the initial screen boots from the cd type 'linux rescue' and enter.

there you go i learned something new, thnak you spicyed

Dunno if it will work, but try Ctrl + Alt + - to decrease the resolution or Ctrl+Alt+Backspace to kill the X server. In the second case, it will probably start again...

Otherwise try what spicyed said and do the following:
cd /mnt
mkdir tmpdir
mount /dev/hdax /mnt/tmpdir [where hdax is the partition of your root system, of course]
chroot /mnt/tmpdir
mcedit /etc/xorg.conf [or vi /etc/xorg.conf]

Now search for the new resolution that you set and remove it for the corresponding color depth. That should do I guess! I hope your FC4 is still there!

Thanks all. I finally solved the issue by hooking up an old CRT monitor and resetting the resolution.