Windows 7, 8, 8.1, Server 2008 R2, Server 2012 and Server 2012 R2 use the following keys for KMS activation;

          Operating System Edition                              Product Key            

                                           Windows 8.1

Windows 8.1 Professional            GCRJD-8NW9H-F2CDX-CCM8D-9D6T9

Windows 8.1 Professional N         HMCNV-VVBFX-7HMBH-CTY9B-B4FXY

Windows 8.1 Enterprise                MHF9N-XY6XB-WVXMC-BTDCT-MKKG7

Windows 8.1 Enterprise N            TT4HM-HN7YT-62K67-RGRQJ-JFFXW

Windows 8

Windows 8 Professional                NG4HW-VH26C-733KW-K6F98-J8CK4

Windows 8 Professional N            XCVCF-2NXM9-723PB-MHCB7-2RYQQ

Windows 8 Enterprise                    32JNW-9KQ84-P47T8-D8GGY-CWCK7

Windows 8 Enterprise N               JMNMF-RHW7P-DMY6X-RF3DR-X2BQT

Windows 7

Windows 7 Professional                FJ82H-XT6CR-J8D7P-XQJJ2-GPDD4

Windows 7 Professional N            MRPKT-YTG23-K7D7T-X2JMM-QY7MG

Windows 7 Enterprise                   33PXH-7Y6KF-2VJC9-XBBR8-HVTHH

Windows 7 Enterprise N               YDRBP-3D83W-TY26F-D46B2-XCKRJ

Windows 7 Enterprise E                C29WB-22CC8-VJ326-GHFJW-H9DH4

Windows Server 2012 R2

Windows Server 2012 R2 Server Standard       D2N9P-3P6X9-2R39C-7RTCD-MDVJX

Windows Server 2012 R2 Datacenter               W3GGN-FT8W3-Y4M27-J84CP-Q3VJ9

Windows Server 2012 R2 Essentials                 KNC87-3J2TX-XB4WP-VCPJV-M4FWM

Windows Server 2012

Windows Server 2012 Core                                   BN3D2-R7TKB-3YPBD-8DRP2-27GG4

Windows Server 2012 Core N                               8N2M2-HWPGY-7PGT9-HGDD8-GVGGY

Windows Server 2012 Core Single Language        2WN2H-YGCQR-KFX6K-CD6TF-84YXQ

Windows Server 2012 Core Country Specific        4K36P-JN4VD-GDC6V-KDT89-DYFKP

Windows Server 2012 Server Standard                   XC9B7-NBPP2-83J2H-RHMBY-92BT4

Windows Server 2012 Standard Core                      XC9B7-NBPP2-83J2H-RHMBY-92BT4

Windows Server 2012 Multipoint Standard             HM7DN-YVMH3-46JC3-XYTG7-CYQJJ

Windows Server 2012 Multipoint Premium             XNH6W-2V9GX-RGJ4K-Y8X6F-QGJ2G

Windows Server 2012 Datacenter                            48HP8-DN98B-MYWDG-T2DCC-8W83P

Windows Server 2012 Datacenter Core                   48HP8-DN98B-MYWDG-T2DCC-8W83P

Windows Server 2008 R2

Windows Server 2008 R2 HPC Edition                   FKJQ8-TMCVP-FRMR7-4WR42-3JCD7

Windows Server 2008 R2 Datacenter                     74YFP-3QFB3-KQT8W-PMXWJ-7M648

Windows Server 2008 R2 Enterprise                     489J6-VHDMP-X63PK-3K798-CPX3Y

Windows Server 2008 R2 for Itanium-Based Systems     GT63C-RJFQ3-4GMB6-BRFB9-CB83V

Windows Server 2008 R2 Standard                       YC6KT-GKW9T-YTKYR-T4X34-R7VHC

Windows Web Server 2008 R2                              6TPJF-RBVHG-WBW2R-86QPH-6RTM4