If you have ever tried to downgrade from a higher edition of Windows 7 to a lower edition, you probably know that reinstalling the Windows 7 with the desired edition is the only way to do it. You get only Upgrade option during the installation process.
Windows 7 users who would like to downgrade from Ultimate or Enterprise edition to Professional or Home Premium edition can use an excellent portable application called Windows 7 Downgrader that helps you downgrade from a higher edition to lower edition easily.
The Downgrader does the job by changing some registry values. Of course, you will need to go through some installation procedure to make it happen. The advantage of using this tool and method is that you will not loose your data or installed programs.
1. Download the Windows 7 Downgrader tool and run with admin privilege. Click the edition that you want to downgrade to and close the application.
2. Put the Windows 7 installation DVD into the drive and run the setup (.exe) file (don’t boot using the DVD). During installation, select the edition that you want to install (downgrade) and then select Upgrade (it’s actually downgrade option) option.
3. Follow the usual Windows 7 installation procedure to complete the downgrade process.