Windows won't activate?

I had windows 8 for around 5 months and then it randomly "deactivated" and when i click activate windows it does nothing at all, I've tried reinstalling windows and all but still nothing..

Any ideas on how to fix without buying another copy?

We will need a diagnostic report to determine the cause.

http://www.eightforums.com/windows-...3-please-read-activation-troubleshooting.html