Windows 8.1 standard/non-Pro edition: 334NH-RXG76-64THK-C7CKG-D3VPT Windows 8.1 Pro: XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB Windows 8 Pro with Media Center: GBFNG-2X3TC-8R27F-RMKYB-JK7QT