Windows Version tells the exact Build of OS  and service Pack you are using. You can simply check it by using “Winver” Command. Open Run Dialog box by using (Win+R) and type “winver” there without quotes. This will bring a Windows which has OS details such as Windows details.

Alternatively you can also use the Command prompt to find the information.Type “winver” in command prompt. It would display all details in command prompt.

P.S. Dont go by Screenshot details of this one. I am using Windows 7 Ultimate RTM @ my deski and would be using the same once i fix up some issues with my Dell Studio.