When I try to activate Windows 8 enterprise I receive DNS error. This was very strange to me because I normally could open web pages in same time.
This was happened because Windows 8 enterprise by default try to activate itself using KMS
So I found workaround on Microsoft web pages and here it is
First you must run Command Prompt as Administrator (right click in lower left corner of the screen)
Then in command prompt you have to type slmgr.vbs –ipk your_product_key
Hit Enter an then you will receive this message: Installed product key your_product_key successfully.
When you check your windows activation you will see that your copy of windows is activated now
NOTE your product key should look a like xxxxx-xxxxx-xxxxx-xxxxx-xxxxx, where x could be any number or character