Vista - Administrator; UAC; Black Screen

When I turn on the UAC and reboot I cannot access the Administrator Desktop
after login.

When I use my User Account (no password) I go to the UAC after logging in
the password and change UAC to No, reboot, I can then access the
Administrator Desktop.

How can I fix this so I can keep the UAC on and access the Admin Desktop?

It was find before until I went into Computer Management > System Tools >
Local Users and Groups > Groups > Users Properties, and notice that my
Administrator account was listed and I removed it. Note: this same account is
listed under the Administrators Properties.

Thanks,
--
Richard