Installed Fedora 5 server, with just about everything in it. Logged in OK at the GUI, setup networking, got on the internet OK, then decided to run the software updates. It started doing its thing, and downloading files, upgrading etc, then it went to a screen saver and froze. After at least 90 minutes on nothing, I rebooted the box and it came back up, but I have no console at all, but I can SSH OK to it and login and SU OK. Any Ideas WTF happened? I am currently running YUM through SSH.

90 minutes probably wasn't long enough, especially with almost everything in it. I've only got a basic desktop and the first update was over 100Mb.
rebooting mid update is definately not recommended!!!
But moving the mouse should have got rid of the screen saver????
So something may have crashed, you may be able to recover by clearing yum and trying again.

It was totally locked, no console response, no ping, no ssh, nothing. Rebooted OK, but it has no console at all, but ssh is working OK. What is the rescue disk for? Will it help?

your getting beyond my help now, I've only booted into the rescue disk disc once just to see what it does, it only gives you a comand line, and you've already got that. You'll just have to hope that somebody who knows what they're doing gives a hand. Sorry.

Are you still struggling or have you reinstalled/fixed it???
I had a few thoughts last night, (this old brain works slow!!!) but rereading your post I think I may have misunderstood.
Are you saying you don't have a gui, or you don't have any terminals at all, (Ctrl Alt F1---6)?
I you have a command line you could try "startx", that may come up with an error message. Logging in as root should give you a amil message, just type mail, and then the number of one of the latest entries, if you can find where it crashed that could be informative.
The log files are in /var/log

If it's only the gui you're missing that could be something to do with X or the gimp.

The downloaded rpms should be in /var/cache/yum (well they are in this FC4 installation). you could CD into the directory that has X11 and/or gnome packages and try to do a verbose forced install with rpm. That might fix it or give you an idea what's happening

I have NOTHING! It is as though the keyboard and monitor arent even connected to it. Once it boots, and gets to the point where the login screen would appear, it is just a dark screen and no keyboard response at all. I can login via ssh though, which means the server is running, but I also noticed that if I try to rerun YUM it appears as though it was never run, the same package updates show up and if I let it run, eventually the whole system stops responding. Looks like I will probably need to reinstall from scratch. Wondering if I should go back one revision to FC4 or RHEL3 instead and give that a try.

you could try centos3.
I'm happy with my FC4, at least now it's in legacy mode there aren't huge amounts of updates! I've just updated it and there was only 10Mb for wine.
Centos is 400Mb! Said no to that, I want to get to sleep tonight.
FC5 is only 58Mb so that's had a "y" It may be worth giving FC5 another try it could have been just a one off glitch.

heheh, the YUM update quoted 1g of downloads when running update. It is at the office and I am not, so come Tuesday, if I have time, I might try something else instead.