I installed rEFIt on two macs. one was a 2007 13 inch macbook and the oher was a 2008 macbook pro. The macbook pro stopped working after installing. there was no chime and the screen turned black. I took out the drive and deleted it. It started to work. the same thing happened to the other one but the hdd is dead and i've been booting externally. I have already removed the hdd. I deleted it from the external disk too. what do I do?