I'm in the same boat, I have installed 10.8 and can boot into it using the usb boot, but I can't change anything that requires admin because it says my password is wrong, I follow tutorial for resetting it in single user mode and I have created 3 more admin accounts all of which osx tells me I'm using the wrong password. I even made the password 1 letter to make sure and it still wont let me log in to admin rights. I can't install chamealion on the HD to get it booting without the usb or get my graphics and network stuff added ether. anyone ever have this problem, I'm thinking of going back to Snow leopard unless someone has any great knowledge about this problem.
