Last night I started having some trouble with my 2011 Macbook Pro. OS X hung on a Safari page I was using and all I got was a lot of beachball and not much else. It seemed to retain some navigational functionality - I could flick between desktops, use the task bar etc but trying to load the Force Quit menu or even hitting Restart wasn't working. After exhausting all the force restart commands I eventually had to hold down the power button and restart that way. I then got the dreaded folder with question mark icon. After a few more attempts to restart, I did actually manage to boot back into OS X, which then seemed to work fine for the hour that I was using it. However, this morning when I started working on it, the OS began to hang again. After a few more restarts it booted again but then same problem...crash then question mark folder. Now it won't boot at all and Disk Utility isn't recognising the hard drive. What would people's advise be? Haven't got a SATA USB caddy unfortunately. Have opened it up and checked the RAM and HD are seated... all seems fine. The logic board was replaced 12 months ago so can't see how that could be the problem. Any tips before I fork out to have it professionally looked at would be appreciated.