Windows 10 Preview ISO build from microsoft - Kapil Sharma

http://windows.microsoft.com/en-in/windows/preview-iso

Preview Product key: 6P99N-YF42M-TPGBG-9VMJP-YKHCF

1. Windows 10 Insider Preview (x64) - Build 10074: 

    http://go.microsoft.com/fwlink/p/?LinkId=522144

2. Windows 10 Insider Preview (x86) - Build 10074: 

    http://go.microsoft.com/fwlink/p/?LinkId=522145

Download it, install and test the build and check the new features report bugs to Microsoft and get rewarded $$$. 

Become a security tester use this opportunity as a security test use case to learn and explore and execute, till that time happy hunting oops... means happy testing ;)