MacBook Pro stuck on apple logo spinning wheel help plz!

[whoknows87]

my laptop was on went to sleep mode , asked me to enter my password , entered the password and just froze no way to force quit, I powered it off and restarted and all I get is the grey screen apple logo , wheel spinning I ran disk utility and chose to repair the HD that was completed and it said the disk appears to be ok, I quit disk utility and restarted and still apple logo + spinning wheel I recently upgraded to mountain lion few days ago and that obviously has something to do with it , I owned this laptop for 2 years and this never happened

What am I supposed to do I do have the Snow Leopard CD's but If I do that wont I lose everything that was on my HD? or so and how will I reinstall Mountain Lion again? purchase it again via app store or will it be stored there?

 

[nitromac]

This happened to me recently. I turned on/shut down the machine a couple of times and it fixed itself. Don't know if that will be the same for you, but doesn't hurt to try. Just wait a bit longer than normal.

Also: remove any USB devices if you have any plugged in. just in case.

 

[whoknows87]

I've been doing that for the past hour or so , I tried the safeboot turned it off hit shift I see the apple logo / grey screen wheel spinning and some loading bar at the bottom it gets to half way and disappears and nothing happens....

I ran disk utility and it said my HD appears to be fine... I have no idea what to do

 

[whoknows87]

I tried nothing I did command R disk utility tried to reinstall OS X it gives me an error any help out there?

 

[Master Talon]

I currently have this problem. Is there a known fix?