Build [at] Microsoft
Windows 10 Installs Automatically On Windows 7 And Windows 8
I can not believe that Microsoft is keeping it quiet - Build 9926 of the Windows 10 Technical Preview can be downloaded and installed via Windows Update on Windows 7 and Windows 8.
For now this method comes with a caveat: a small file is needed. Users go to Microsoft’s Technical Preview page and click the ‘Start upgrade now’ button. This downloads the file, you run it and afterwards you will be prompted to restart your PC. On first boot Windows Update will now show ‘Upgrade to Windows 10’ as an option. Say goodbye to burning DVDs, making USB boot drives and fiddling with bios boot order settings.