I get an error while trying installing SQL Server 2008 R2 on Windows Server 2008 R2

I get the following error while trying installing SQL Server 2008 R2 on Windows Server 2008 R2

The following error has occurred:

Attempted to perform an unauthorized operation.

Click 'Retry' to retry the failed action, or click 'Cancel' to cancel this action and continue setup.

For help, click: http://go.microsoft.com/fwlink?LinkID=20476&ProdName=Microsoft+SQL+Server&EvtSrc=setup.rll&EvtID=50000&ProdVer=10.50.1600.1&EvtType=0x88792597%25400xBB814387

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BUTTONS:

&Retry
Cancel
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