Yeah, I faced it and there was a discussion about this at the Fedora Core list as well.
But thing is this is a bug in Fedora Core 4.Quite a serious one dude, especially if you cant switch to Virtual Terminal after X has loaded using Cntl+Alt+Fn.Finger poining to Somebug in latest X.org offering will not do.
For people who have stumbled here, try the below suggestion. It worked for me.
From Mike A. Harris
Bojan: Please try replacing the libvgahw.a module (after backing up the
original), with the following one:
This one is taken from the latest FC3 errata release, and many people
claim it solves the problem. If you could confirm this for me, it would
help us in solving the problem for a future update.
Thanks in advance.