Hi My Powermac G5 has started to act really strange and unstable. Almost all the programs i use on it (exept itunes for some reason) crashes all the time, and I get the restart your computer in four languages crash, about twice a day. If it was a pc i would think it could use a defrag, but i heard that you don't have to do that on osx. I really have no idea where to start.. i think it's a harddisk problem.. Anybody have surgestions?