My PC was closed for 3h and when I started it this morning,I got some kind error"Code: OxCoo4Coo3".Everything has been worked fine and this morning I found that this windows is not Geniune or something like that. I haven't update my windows 8 ultimate even for weeks, so I think I shouldn't have to get some kind error.

Hi,

I think perhaps the long-time inactivation has disabled some of the features on your computer. Maybe the right product key for Windows 8 activation can do you a favor! You can have a try!

Seems that your Windows 8 is not the genuine copy. It may modified by someone else. So try to download a genuine Windows 8 and install it again. Then try the Windows 8 activation again with your product key

The Download page IS A JOKE?
It is just a Image page dude!