Hi I am a new mac user so please be patient with me. I just purchased an ibook g4 from my friend. It needed a new hard drive so I just had that replaced. The first day it worked fine. But now it keeps freezing. Half the time I can't even get it to boot to the desk top. Like right now for example. I got it to load to the desk top but I clicked on the hard drive and the cursur just keeps spinning. Everytime I try to run safari it crashes. So I downloaded internet explorer and that keeps crashing too. Now I can't get it to work for more then a second until it freezes. What can I do?