Vista Time Synchronization

I recently went into Change Date & Time Internet time tab and chose
time standard to connect with. After doing that I went onto th
internet and connected with time.nist.gov and checked the time. Afte
that I was no longer able to go into the internet time tab. It tells m
that time.nist.gov is the time connection and I can't change it. I
tells me I need to have permission to do this as administrator. I a
the administrator! What goes here? Can anyone help

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RHMinetti