Microsoft Europe has inadvertently announced the date of Window Vista through a competition it is running on its site.

Perhaps not sure itself when the company will release the next version of its operating system Windows Vista, Microsoft in Europe is inviting visitors to its site to guess the launch date for them.

However a blogger, called Thomas at teezeh.info, has found that after you submit a date, it plays a "hint" video.

Looking at the source code for these videos, they are hosted on a Microsoft server in Switzerland. And depending on your guess, they are being loaded either from a subdirectory /early/ or another one named /late/.

From this, his site states that "By simple iteration he quickly found that /early/ ends Nov 30th while /late/ starts Dec 1st. So either one of these will be the launch date. If this all is not a dirty little trick from the webmaster, of course!"

Those who decide to enter into the free competition will be in with the chance to win an exclusive invitation to the international Vista launch even in America.

To enter you must be a member of the Beta Experience campaign, and Micorosoft is opening this up to anyone who lives in Belgium, Croatia, Denmark, Finland, Germany, Hungary, Ireland, Italy, Norway, Pakistan, Poland, Portugal, Romania, Spain, Switzerland, UK who are 18 years of age or older.

You can enter the competition at

microsoft.com