MBP Failed to boot after OS X install...

Just had a rare occurrence happen and kinda freaked me out a little..

I restarted my mbp, and the apple logo came up and then the spinning wheel at the bottom showed up. Normally it does 3.5 full turns before the OS loads up, well this time it kept spinning and after a minute or so the apple logo turned into a crossed circle.

I had to hold the power button to restart... what just happened?? hardware issue?

I since tried to duplicate the problem, but no luck.

I'm using a X25M SSD

 

Cool, thats a relief

What do you think would cause it to hang?

 

anyone?