Given that a 3GHz processor and 1024 MB of RAM are plenty for Ubuntu, insufficient memory isn't an issue.

Are you sure the computer BIOS is set to boot up from CD before booting up from the hard drive?

Are you sure that the Ubuntu CD is in good condition?  I recently had difficulty with an antiX Linux live CD.  (It booted up, but certain things didn't work.)  The md5sum showed no problems, but the CD was scratched.  I burned antiX Linux to a new CD and had no problems.  So I think certain distros and/or CD drives are finicky.   

I also learned earlier on to boot antiX Linux only on a CD-R and not a CD-RW on my two old desktop computers.  For some reason, they had difficulty booting up antiX Linux on a CD-RW but had no problems with antiX Linux on a CD-R.  Strangely enough, I had no trouble booting up other distros (like Damn Small Linux, Puppy Linux, and minimal command-line-only Ubuntu) on a CD-RW on the same computers.  Again, I think certain distros and/or CD drives are finicky.

On Tue, 3 Aug 2010 11:53:13 -0500 (CDT)
Thomas Rieff <trieff at greencaremankato.com> wrote:

> Jason,
> Thanks for responding. I have 1024 memory installed.
> It is a P4P800MX with a 3.0 GHz processor.
> I have been using Win 2000, to avoid the upgrade mania it creates.
> Our customer database is written in Visual Fox. It is my goal to convert in the next 5 years to a browser based, os independent system. Good reason to follow the open source, Linux based software systems.
> I can try a different Linux distro. Its just that I had the ubuntu cds laying withing arms reach. 
> Tom
> 
> Thomas Rieff 
> GreenCare 
> 1717 3rd Avenue 
> Mankato, MN 56001 
> (507) 344-8314 Office 
> (507) 344-8316 Fax 
> (507) 381-0660 Cell 
> 
-- 
Jason Hsu, embedded engineer, Linux user <jhsu802701 at jasonhsu.com>