Administrator in Windows 7

Close Outlook and relaunch Outlook by Right Clicking on the shortcut and "Run as Administrator". Then remove the add-in

Please start outlook by running it with administrative permissions or disable UAC temporary.

Is there an echo in here?

You need to run outlook in safe mode to remove add-in. Run the following command to start outlook in safe mode.

   outlook.exe /safe

1. run outlook.exe as admin by right click
2.can delete the addin from registry HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\Outlook\Addins AND
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Addins. Restart Outlook/machine

for all above same account should have admin access

Try to use the build-in admin account if Run as Admin mode did not work.
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1.       Click the Start button, and then type cmd in the search box.
In the search results list, right-click cmd, and then click Run as Administrator.
2.       At the command prompt, type net user administrator /active:yes, and then press ENTER.  
3.       Type net user administrator <Password>, and then press ENTER.
 Note:  Please replace the <Password> tag with your passwords which you want to set to administrator account.
 Type exit, and then press ENTER. Run Outlook as this administrator account again.