How many times have you had to restore your computer's operating system (Windows) but lost the recovery CDs or didn't create them?
Fortunately, there is a way! All you need is a Windows ISO (i.e. the entire Windows operating system in one file) and the free Ei.cfg Removal Utility which deletes a key file inside the former allowing you to install any version of Windows.
There is a special feature regarding the Windows 7 and 8 installation versions. These versions are designed to match the product key. This is why you cannot install Windows 7 Professional on a computer with Windows 7 Home Premium, even if you have a CD for the latter.
This is where Ei.cfg Removal Utility comes in . If you somehow get your hands on, say, a Windows 7 Home Premium CD with a license for the same operating system, Ei.cfg effectively creates a universal Windows ISO that will install any version that matches your product key.
The process is simple. Borrow a friend's install CD/DVD, copy the ISO to your hard drive, then run Ei.cfg and then use the Rufus to boot the "hacked" ISO onto a flash drive to install Windows on your computer.
Now, simply boot from the flash drive and choose to install the version of Windows you are licensed for. Enter your key and you are ready to go! And remember, your key will only work for the version it is intended for!
In case you can't find an ISO for Windows while you have a valid license, Microsoft has taken care of it. There is an official ISO of Windows 7 SP1 here & Windows 8.1 here.
