Ok I did a upgrade to 10.4 from 10.2, but it didn't seem to like it so I want to try and format and then install 10.4 but it now didn't boot from the DVD drive. What do I do?

*Update* I got 10.4 on, so much faster with a clean install, now im just updating. Then im going to up the ram. Would a faster and bigger HD make a difference from the 12gb one in it now?What OSX do you guys suggest for b/w g3s?

A screenshot of my HD from system profile