gunna get the boot

hey i own a pm g4 and i recently installed a new dvd drive. the dvd drive is working fine but when i turn on the computer it doesnt go any further than the apple loading screen...whats wrong and is there anyway i can fix it? a few weeks ago a compusa guy did a " apple check " or something and it seemed to make it run real smoothly. what is that and how could i do that?
any responses would no doubt help me alot.

 

um

temujin, what i meant to say was, that it was working fine.whoops.ill get back to you guys after i try and do what you said.

 

hey temujin

you said that your computer had lines. thats probable the logic board. you could of done that yourself.