Mac OS X will not start up but if i hold option i can boot from windows vista. My vista does say incorrect partition 80 when its boot booting but it does start up. I have tried booting up from the leopard install disk but when i try to do anything with it it just says mac os x can not be installed on this computer. The problem, is that when I boot from OS X it just pretends to load and then says that You must restart your computer by holding the power button or by hitting restore. Any Help?