This is the keys you need for activate the Windows 10 Technical Preview.
Windows 10 Technical Preview build 10041: NKJFK-GPHP7-G8C3J-P6JXR-HQRJR
Windows 10 Technical Preview build 10074: 6P99N-YF42M-TPGBG-9VMJP-YKHCF
Windows 10 Enterprise Insider Preview build 10074 and 10122: VTNMT-2FMYP-QCY43-QR9VK-WTVCK
Help shape the Windows 10 experience for millions of people