I've had a few issues with software today. But although my Mac now turns back on several issues have arisen that I can't fix: 1) Apple Mail won't load, it just crashes before it opens. 2) When I plug my external hard drive in to perform a Time Machine Back up the machine crashes and I get the black Dialog box telling me to power off my machine. 3) When I try to perform a software update at the very last minute of the install I get an Error message and the update fails. Really frustrating and so any help is appreciated.