The Verge writes, It's no secret that Microsoft is planning a big marketing campaign around Windows 8, but one estimate suggests that the company could be willing to spend between $1.5 and $1.8 billion. The huge sum, reported by Forbes, would be around triple the amount that the company allegedly spent on its Windows Phone 7 launch two years ago. The Wall Street Journal reports that the ad campaign will kick off this weekend alongside pre-orders of some Windows 8 PCs and tablets. Microsoft has reportedly been working with advertising agency Crispin Porter + Bogusky to prepare its Windows 8 ads. Although these...