XBMCbuntu 12 Beta 1 will not start... boots to text login

Hi ,

I have completed this setup like 3 times now but cannot figure out why after completing setup from usb key the first system boots after setup boots normal but all subsequent boots to a shell login prompt. I can login fine from that point but if I try and startx the window blinks and returns to prompt. sorry if my discription is vague as I am still learning Linux

The system was running xbmc live 11 without issue so Im kinda thinking I must have some kind of nvida driver issue. system is Asus AT5IONTI

thanks in advance ,

Strato