G4 powerbook
 

Hi all

i have been working with PC's for 15 years but this is my first experiance with Mac operating system so please bare with me.
After updating my G4 with combo update i restarted it and it keeps giving give needs to resart evry time i reboot endless loop i can boot in safe mode ok.
is there anyway i can remove this update?
i have no software which came with it as i got it second hand as is can anyone help
if a re installation is required can anone please give me a detail eplaination of what i need and how?
thanks all