I've just watched the following video of a vSphere 5.1 install on a Windows server
http://www.youtube.com/watch?v=Sps0O3MDPjs
At the end he did something I didn't know you needed to do or could do which was to install the vSphere client on the same machine and connect to it using his Windows credentials. I've only used the client to connect to ESXi servers up to now. However, when I try this I get an 'Unable to connect to the remote server' error no matter what login I try. What am I doing wrong here? What login does it need?