Just as you were getting comfortable with Windows 7, it looks like Windows 8 is coming in the next two years. In a post celebrating the one-year anniversary of Windows 7 — the fastest selling OS in history — Microsoft’s Dutch Web site briefly mentioned the construction and release of its successor:

“Microsoft is on course for the next version of Windows. But it will take about two years before ‘Windows 8′ on the market.” Winrumors.com grabbed and translated the post, and CNET took a screenshot of the text, which unsurprisingly disappeared shortly after the news stole headlines. Now Microsoft is back to being tight-lipped about Windows 8 and its expected release.

Windows 8

Microsoft has let slip that it expects the next version of its Windows operating system to tip up in two years.

The revelation came as part of a birthday celebration for Windows 7, with the firm saying that “it will take about two years before Windows 8 [is] on the market.” Most of its operating systems typically appear around three years after the previous version, though the Vole, like many software companies, is very cautious about making predictions about upcoming products.

The problem for Microsoft is that now that its customers, especially its bread and butter enterprise ones, have a whiff of when the next Windows, or Windows 8, will be released, that might put them off from purchasing the current version. Perhaps knowing this, the firm announced a rather vague “first half of next year” release date for its Windows 7 service pack 1 (SP1).

Last week Microsoft CEO and impressario Steve Ballmer claimed that the firm’s biggest challenge would be Windows 8. That’s probably the most accurate statement Ballmer has made in some time, with Apple’s computer sales continuing to grow and Linux becoming a bigger threat with every passing day. For many of its users the biggest selling point of Windows 7 is that it is not Windows Vista, but that’s not going to be the case with Windows 8.

Although Windows 7 is an improvement over Vista, the Vole will have to pull something major out of its hat with Windows 8 to entice people to upgrade from Windows 7 and not consider alternatives. Going by documents leaked earlier this year, there is relatively little in Windows 8 at this point to get users salivating.

Microsoft will be hoping that its customers won’t wait two years to purchase another version of Windows, although if Ballmer is to be believed, the biggest question mark at this point is whether Windows will be worth spending more money on to upgrade when Windows 8 arrives.