Hello Bagavan,
The Windows 7 SP1 is currently not a final release yet, and is only a beta version right now. After you installed the beta SP1 is makes your Windows 7 an evaluation copy since you are now testing Windows 7 with beta SP1. This will be like this until you either uninstall the beta SP1, or when the final SP1 version is released, uninstall the beta SP1 and install the final release SP1.
Hope this helps,
Shawn