Seen a few posts on here but none have bothered to post specs to be able to gain help.

So, I would like to install Mountain Lion on my Alienware X51 (for the heck of it)

I tried but it hands on the grey screen with spinning wheel (the coloured mouse wheel)

The specs are:
i7-3770
GTX 660
1TB HDD
8GB RAM
Blu-Ray Drive

the only problem I can see with the installation is the motherboard, it uses a custom socket 1156 alienware branded motherboard.

Any tips?