Ubuntu Installation :: CD Fails - Installer Can't Get Username Or Password?

I am trying to install Ubuntu as a secondary operating system on my Windows 7 PC.

System specs as follows:
AMD Athlon II X4 620 Processor 2.6 Ghz
4.00 GB RAM
ATI Radeon 4600 series video card

I downloaded the 32-bit ISO image from ubuntu.com and burned it to a CD. When I try to boot, I get a purple splash screen with a couple of icons on the bottom. Shortly thereafter, I get another screen that says Ubuntu and has 5 dots on it that change color from red to white in sequence. During this time, my CD drive is active. After a very long time, the drive goes quiet and I get an error that the installer can't find the username or password. I don't remember the exact text of the error message. The system was hung and required a hard boot to recover.

Reading these forums, I rebooted the computer and this time pressed the escape key once the display had changed to the Ubuntu with the dots. The username/password error came up quickly and was followed by several "Bus error" messages. I ejected the CD and restarted the computer in order to come here for enlightenment. I'm reasonably good with Windows but a total neophyte when it comes to Linux. I'm going to try it again and this time record the exact error message (which is what I should've done initially).

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