MBP Hangs when restarting
I have a 2010 MBP A1278. 2,4Ghz Core 2 Duo, 16Gb RAM, 750Gb HDD, latest Yosemite OS updated to current build.
When I restart or reboot the computer (on the three occasions when it just hasn't been responding, despite leaving it for an hour), the computer hangs at the spinning wheel and gets no further. The wheel just keeps revolving on the black screen but the computer doesn't do anything else at all.
I've checked disk integrity via Onyx and it's fine.
I've read that resetting the SMC could help but the Apple Support page says only do this as a last resort (as if implying this is a make-or-break kinda deal).
As i'm new to Macs, doubtless i've not supplied some information that would help someone assist me but i'd really like to know what I could do to stop these hangs on reboot please.