Glad to hear that this worked ... I've got the same problem once, and found the thread about this here http://answers.microsoft.com/en-us/windows/forum/windows8_1-windows_store/just-updated-to-windows-81-and-the-windows-store/c4cf204d-bd99-426c-b800-9c9125ae739c According to Luis Cantero's...
have you try this one ? paste this command line at Command Prompt (run as administrator) ... powershell -ExecutionPolicy Unrestricted Add-AppxPackage -DisableDevelopmentMode -Register $Env:SystemRoot\WinStore\AppxManifest.xml