Clarification: the installer works fine, it's just messing up after install, but before you see the login screen for the first time, right?
If so, this sounds like a problem with the X Server Configuration.
Can you boot into a command line (recovery) mode? (It may automatically put you in this mode after a few seconds of the weird monitor display.)
If so, try and grab your xorg.conf and your Xorg.0.log so we can see them. The easiest way to do this is to copy it to a floppy or, if you have a livecd that can read your partition, just somewhere on the partition. The goal here is to grab these files and put them up at
www.pastebin.com.
Try:
Code:
sudo cp /etc/X11/xorg.conf /your/destination/path/here
sudo cp /var/log/Xorg.0.log /your/destination/path/here
If you can't get them somewhere where you can access them, use the command "less" instead of "cp", and write down any lines that have "!!" or "!!!" in front of them, as well as the last 3 lines of the log.
I'm having a little problem with X too. Misery loves company. :]