I installed windows xp and i recently deleted it through boot camp since i just bought a Alienware computer with windows on it. Now when i boot my macpro, It gives me a "disk boot error" and the only way for me to restart is the power button. The only way i can start up my macpro now is to hold 'option' down and choose MAC when it gives you the OS options. Does anyone know how to fix this because most of the time i forget to hold down the option button and this is really annoying.