Hello, I just purchaed Mountaion Lion, but I can't install it. The installer keeps saying "This disk cannot be used to startup your computer" even though I am using that disk right now. I tried making the partition smaller, like the support document said when updating from SL to Lion -- I am going from Lion to ML. I checked to see if my MacBook is supported and it is. Maybe it has something to do with my computer not having a Recovery partition (I was trying to dual boot Ubuntu [unsuccessfully] and ended up messing with a bunch of drive stuff) Can somone please help me, I'm stuck! I am running OS X Lion on a Late 2009 White Macbook Thanks.