Microsoft says Windows 7, its new Vista-replacing operating system, will be generally available on Thursday October 22, a month ahead of Black Friday, the traditional holiday shopping kickoff in the states and three months ahead of its supposed schedule.

Need anyone reflect that Microsoft absolutely had to get the thing before Christmas or face increased revenue shrinkage?

It said last month that it would but hasn’t given a precise date until now. OEMs are supposed to get their golden masters around the end of July for validation exercises. Folks who buy a new computer before October 22 will be entitled to an upgrade.

Meanwhile, Microsoft has relented on its intention to prevent Windows 7 Starter Edition, now positioned as a netbook OS although any of the Windows 7 SKUs will run on the widgets, from running more than three apps at time.

Microsoft’s also going to offer the 7 Starter Edition worldwide rather than limit the cut to third world markets the way it has with past Starter Editions.

It wants to ensure it gets more reactions like PC World’s, the largest electronics retailer in the UK, which according to Microsoft’s own Brandon LeBlanc is dumping all of the Linux small notebooks in their stores and going all-Windows.