Member of domain admin group but don’t have local admin rights on Windows 7

I am a member of the domain admins group on my W2k3 server (DC), when I login to my new Windows 7 Enterprise machine with my domain admin account I have no local admin rights. I can’t register Active X files or perform installs! I’ve added the domain admins group into the local groups on my machine and I’ve also added my domain account into the administrators group on this machine but still no joy.

Does anyone know why this is?

Thanks,

Chris