From this page you can learn how to ReFormat Windows 10 32-bit / 64-bit & Other Microsoft Windows 7, 8, 8.1 OS Without CD / DVD.
Over time, a hard drive tends to become slow and bog down a PC. This may be as a result of prolonged usage without proper software maintenance, exposure to viruses, or due to the installations of programs that conflict with the PC. Whatever the reasons might be, wiping the drive completely of its operating system is often required to make the PC function optimally. In this tutorial, well focus only on Windows and how to reformat Windows without the use of a bootable CD. Please note; formatting the C drive or the drive that holds the operating system is not like formatting other drives because you must not be within Windows when you do it You need to format the Windows OS while you're elsewhere other than in your installation. Also, if you just want to learn how to reformat Windows 7, 10 and 8 without CD, because you want to install another set up of windows, note that it is not practical to continue with this tutorial. The formatting option is provided automatically when installing a new Windows setup.