Problems bootinb/installing

[Ashley M. Kirchner]

    I have an old IBM Netfinity 5000 that I'm trying to put Ubuntu on.  
It has a built-in S3 video card which automatically gets disabled when 
the system boots up because I have a Matrox G450 dual head PCI 
installed.  When I had Fedora Core on this machine, the installer 
automatically ignored the S3 and installed the Matrox X.org drivers 
instead and all was fine.  However, if I try the same with Ubuntu, for 
some reason it wants to run with the S3 driver.  But because of the way 
the card gets disabled, Ubuntu can't use it - it ends up displaying a 
bunch of messages saying that there's no memory available for any of the 
resolution settings.  Well, that's true, but why won't it detect and use 
the Matrox card instead (which is where the monitor is plugged in anyway 
and the signal is going there too.)

    Furthermore, when I pull the Matrox card off and try to run off of 
the internal S3, Ubuntu gets to the point (after loading all drivers) 
where it's trying to load X, the screen flickers once or twice then 
everything goes black.  If I switch to any of the vterms (ALT F1-F6), 
they're all black.  I get a beep if I try to hit backspace on those 
vterms (indicating that the cursor is at the beginning of the line) but 
there's no display.  Nothing happens from that point on.

    So, I can't run the live CD nor install Ubuntu using the built-in S3 
card whether I have it enabled or whether it gets disabled due to 
another card being plugged in.  FYI, the disabling of the S3 card 
happens automatically when you boot the machine up.  I get a message 
during POST that says, 'Planar video disabled due to plug in video card.'

    Anyone have any ideas or suggestions (other than shoving this beast 
of a machine off of the balcony and drive over it)?