I just upgrade to win8.1 from win8 and I can\'t start wamp server (2.2 x64)

Apparently Windows 8/8.1 are missing some essentials. The solution is to install Microsoft Essentials for Windows 8/8.1. This adds the .NET framework with all the necessary APIs that allow Wamp to function as designed. You can download Windows Essentials from herE: http://windows.microsoft.com/en-us/windows-live/essentials . I have already tested this out on several devices, including my laptop and desktop running both Windows 8 and 8.1. Good luck! :)