Here is something that works for EVERYONE.
Step 1. Go to command prompt.
Step 2. Type/paste in this:
slmgr -ipk NG4HW-VH26C-733KW-K6F98-J8CK4
slmgr -skms win8kms4.mooo.com
slmgr -ato
slmgr -ckms
Step 4. If it gives you any error then please open Command prompt as Administrator.
If that doesnt work please give me a reply or a PM.
Hit thanks
-Remco.