After creating partitions, computer won't boot from CD

Dell Inspirion 8200 1.7 Ghz Pentium 4 processor, 128Meg RAM 30 Gig hard drive, trying to install VL 6.0 Light.

Once I put the CD in and booted it from the CD it came right up and I went through all of the partition settings and did all 3 partitions, and wrote them and then rebooted it like i'm supposed to, after the reboot it tried booting from the harddrive from the old Windows XP that was on it. It failed of course because I just erased and repartitioned the drive, but now it won't boot from the CD to finish to install of VL. I played with the BIOS and it definitely set to boot from the CD drive before the internal drive. Any help?

Also on a seperate note and this has nothing to do with VL, but I think I've got a hardware problem with this computer, the input hardware (Keyboard trackpad and eraser head mouse) only work every couple of seconds for maybe a second or two. any idea what that may be? should I just junk the computer? I want to put 1 Gig of RAM and turn it into a really nice calculator for my engineering homework. But before I'm going to put any money into it I want to make sure the computer isn't just junk. I would love to run MathCad and MatLab and Silverfrost compilers, thats all I want the computer to do, nothing else. I know those programs are only compatible with Windows, but I have found a couple replacement programs that I think would work wonders, like Octave is a MatLab replica, anyone know of a MathCad replica? that would be incredible. Thanks again for your help.