10.04 install not working on older machine

does Ctrl+Alt+T or Alt+F2 works?
if the do write "gnome-panel" then hit enter

I believe the minimum is a P5. a P3 is too old.

Recommended Minimum System Requirements

The Recommended Minimum System Requirements, here, should allow even an inexperienced user to easily install a usable system with enough room to be comfortable. A good "rule of thumb" is that machines that could run XP, Vista, Windows 7 or x86 OS X will almost always be a lot faster with Ubuntu. Simply try Ubuntu CD as a Live CD first to check the hardware works.

Ubuntu Desktop Edition

    * 1 GHz x86 processor
    * 1GB of system memory (RAM)
    * 15GB of hard-drive space (although this can be split onto 2 drives, a 5Gb / and a 10Gb /home fairly easily)
    * Graphics card and monitor capable of 1024 by 768
    * Either a CD/DVD Drive or a USB port (or both)
    *

      Internet access is helpful

Hardware produced in the last few years or with an efficient architecture or machines built for a specific purpose can often work well with less. For example, a netbook with an 8GB SSD will work well although there wont be much room for saving stuff directly onto the drive so Ubuntu's free 2GB Cloud could help a lot. A machine with a crumbling, 15 year-old, slow, 8GB, IDE hard-drive probably won't and doesn't really compare with the netbook anyway.

Machines that are 10 years old or more and that don't meet these guideline will probably require some work to revive; the obvious choice would be to try a lighter-weight distro rather than try a minimal install of Ubuntu. Obviously we hope that a distro such as Xubuntu (see below) can keep you in the official Ubuntu group or one such as Lubuntu or Debian might keep you in the same family. However it might be worth looking further afield at distros such as Wolvix, sliTaz (slightly French) or in extreme cases Puppy. Explore from the main pages at DistroWatch

    *

      http://distrowatch.com

The easiest and most effective step towards a minimal install of Ubuntu is to install a lighter-weight Desktop Environment such as Xfce (see Xubuntu below), LxDE (see Lubuntu (not officially supported yet)) or Enlightenment to name just a few of the most popular. Some of the larger applications, such as OpenOffice, could be swapped for very much lighter equivalents but for more information about doing a minimal install please see the guides

    *

      https://help.ubuntu.com/community/Installation#Minimal%20installations

you can also look at this
http://lightlinux.blogspot.com/2009/02/lightweight-ubuntu-derivatives-for-old.html

   David
   in TN

Could you type Ctrl+Alt+F1 and see if you get a prompt.
Lot of issues are related to graphic card management.

I'm not sure what happened, but everything appears to be up and running! I was away for the weekend, but when I got to the machine yesterday, it worked just fine (if only a little slow, I blame the hardware).

Thanks for the great answers everybody! I really appreciate the support!