Now here’s a wheeze. Microsoft has put up a game on its website allowing you to guess the launch date of Windows Vista.

Take a guess and you get shown a video which gives some clues of the true date.

But do they know the date themselves? Hasn’t the release of Windows Vista been a moveable feast for ever?

Someone, though, has worked it all out and claims it’s December 1.

By simple iteration I 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…

Can this be true?

We know Windows Vista machines need to be on the shelves by very early December.

And the manufacturers will need three clear months before they’re ready to ship. Therefore the later the date pitched, the more likely it is to be correct.

December 1 sounds about right. Any later would create anxiety in the consumer market. Earlier in November seems out of reach to the OEMs.

Enterprise machines can wait until 2007.