Download the ISO image of Windows 10 Build 10041 directly from Microsoft
When Microsoft released the latest build of Windows 10 Technical Preview it only made it available to Windows Insiders on the Fast ring, and only through Windows Update. It has now made it available to those on the Slow ring too, which means there are now official ISO files to download.
If you need to perform a brand new install -- either on a spare PC, or to run in a virtualized environment -- then grabbing the ISO image file is the easiest, not to mention quickest option.
There’s a separate page to download the ISO files for the Windows 10 Technical Preview March Update as Microsoft is calling it.
Go here, choose the language and version you want, and the download will begin.