Mountain Lion no longer boots

[mrtomcat]

I had my hackintosh run perfectly without any issues for the past several months now. A few days ago I noticed that once I had not been on the machine for 12+ hours (I leave it on) the screen would not turn on again, so I rebooted and all was fine.
Today the same problem but the reboot would go as far as the grey boot screen and then the machine would shut off.
I have a dual boot into windows 7 and that booted with no problems...
I then tried booting from a cloned drive and the grey screen would come on and just sit there and eventually there is a crossed out circle image on top of the apple logo.
I then tried to boot into unibeast from the USB stick, same results.
The bios looks fine, nothing seems to be over heated and I am clueless to what the problem is.

Any suggestions?

Thanks

 

[mrtomcat]

To add a bit more detail. I did run with -x and the same thing happens, it boots to grey screen and then shuts off.
Then I tried -v and it shows several error and noting it cannot launch Mountain Lion but then shuts off before I could not write down the error because the machine shut down to quickly. I am going to try and take a picture this eve...
It feels like some went bad on my bios... so weird.

Any help is appreciated