Trouble booting to a CD

Whenever I try to boot my G5 to a CD, the screen gets wavy and I can't see what I'm doing. I am running 10.2.8 and was trying to upgrade to 10.3 when I first encountered this problem. Then I tried running the disk warrior utility to find out if something was wrong with the machine, but I can't run the utility since I can't see anything on the screen except for many wavy lines. This only occurs when booting to a CD. The OS recognizes the CD when booted to the Hard Disk.

Also sometimes at random the display size will change from 1024 x 768 to 800 x 600 and I need to restart to fix it.

Thanks for the help.