quick question when you format your HD as a mac osx on a single drive and you format it for journled hfs+ should it be guid or still mbr in the options.

I have tried to install it three times and it has failed everytime.

my specs
a8n sli deluxe (asus) 939 mb 3800+X2 6600 nvidea graphics card 2 gigs of ram and a SIIG fire wire 800 card in the box