World's biggest Company Microsoft is right on schedule, has made the Windows 10 Technical Preview and is  available to download. They launched 64-bit and 32-bit  available for it's users English, Chinese, and Brazilian Portuguese.

Be prepared for Window 10  .

As always with preview version of softwares you shouldn’t install it unless you’re fully prepared. This means you should back up any important files, and ideally you should have a separate hard drive/partition to install the Technical Preview on. You cannot revert from Windows 10 Technical Preview to Windows 7 or Windows 8; if you have second thoughts, you will have to reinstall from scratch.