There are at least two possibilities.
1. The on line source scammed you.
2. The license is genuine, and you need to make the phone call to MS
(There are a number of reasons why on line activation can go awry.)
<Arnelbee from Dublin>; "Ireland" <Arnelbee from Dublin,
Ireland@xxxxxx> wrote in message
> I UPGRADED MY XP TO HOME PREMIUM VISTA AND SUCCESFULLY ACTIVATED WINDOWS
> WHEN I BOUGHT AND UPGRADED TO ULTIMATE BY BUYING DIGITAL LICENSE ON LINE,
> AFTER A SUCCESSFUL INSTALL , I COULD NOT ACTIVATED WINDOWS ULTIMATE AND IT
> SAYS THAT I HAVE 1 MONTH TO ACTIVATE WINDOWS.THAT THE PRODUCT KEY HAS BEEN
> USED ALREADY..
> NOTE: I AM RUNNING A DUAL BOOT XP AND VISTA ,HOME PREMIUM OS WAS INSTALLED
> IN DISK D.
> HELPPPPPPPPPPPPPPPPP!!!! please....