Windows 7 Windows 7 Ultimate - unable to accss pc via remote desktop

Hi, I don't use Windows much so excuse me if I am asking basic questions here.

Today is the first time I have had to access my work pc remotely so went out and bought Windows 7 Home. I accessed my works VPN network via the browser (have an icon in my taskbar called "network Connect" which tell me how long I have been connected for), I was able to ping my work PC but when I tried connect via Remote Desktop I was getting an error:

Remote Desktop can't connect to the remote computer for one of these reasons: 1)Remote Access to the server is not enabled 2) The remote computer is turned off 3) The remote computer is not available on the network Make sure the remote computer is turned on and connected to the network, and that remote access is enabled."

To cut a long story short realized that for whatever reason Remote Desktop is not enabled on Home so upgraded to Premium. Now I am not only can I not remote into my work PC, I can't even ping it.

Any ideas? I have Googled the hell out this and am just going round in circles.