Windows 8.1 RTM Pro Offline Activation RETAIL Keys
[Windows 8/8.1 Pro Retail Key for 8/8.1]
slmgr.vbs -ipk 6GN7R-2MQWJ-4FHKJ-7Y98G-YG8KB
slmgr.vbs -ipk N6VDM-4JG7W-QBPT4-6WJMG-WXBCY
slmgr.vbs -ipk GX3NG-998CM-94XDX-DDGCK-RM32Y
[Windows 8.1 Pro/Enterprise MAK Key for 8.1 only]
slmgr.vbs -ipk MPN6V-8KD8C-WKQ4F-B4C7B-MY33Q
slmgr.vbs -ipk HVC82-BNRRP-K6Q4G-Y89FY-DPC7D
slmgr.vbs -ipk FPYD2-NY3YK-TH6M2-8Y474-WFFX3
slmgr.vbs -ipk P8H8N-PX6FV-MHMBD-RXJH7-YY33Q
slmgr.vbs -ipk NYG83-V8PJ2-7DMVV-CDRKT-FVTVD
***If any key failed try to use another one****
[Tested working on VM1 22 October 2013]