Clean Install Windows 7 With Windows 7 Upgrades

Martin Brinkmann
Oct 24, 2009
Updated • Jan 10, 2012
Windows, Windows 7

Windows 7 can be purchased in various editions like Windows 7 Home Premium or Windows 7 Ultimate. Next to these editions are also different versions of the operating system like oem, full retail and upgrade. If you purchase a Windows 7 Upgrade you are only allowed to upgrade if you own a previous version of a Windows operating system. But what if you want to perform a clean install on a new computer system? The installation using the Windows 7 Upgrade DVD would work fine but it would not be possible to activate the operating system.

Paul Thurott discovered a way to perform a clean install of Windows 7 using Windows 7 Upgrade media and to activate it with just a simple tweak which can be applied in the running operating system.

According to Paul all that needs to be done after performing the initial clean installation of Windows 7 is the following:

After performing the clean install, ensure that there are no Windows Updates pending that would require a system reboot. (You'll see an orange shield icon next to Shutdown in the Start Menu if this is the case).

Then, open regedit.exe with Start Menu Search and navigate to:


Change MediaBootInstall from "1" to "0".

Open the Start Menu again and type cmd to display a shortcut to the Command Line utility. Right-click this shortcut and choose "Run as administrator." Handle the UAC prompt.

In the command line window, type: slmgr /rearm

Then tap ENTER, close the command line window and reboot. When Windows 7 reboots, run the Activate Windows utility, type in your product key and activate windows. It should just work.

There you have it. An easy way to do a clean install of Windows 7 using an upgrade DVD. This is obviously only legal if you own a previous Microsoft operating system that's supported by the Windows 7 Update program.


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  1. Anony said on December 26, 2012 at 8:52 pm

    Fantastic! thanks for your help

  2. Anonymous said on March 16, 2012 at 5:21 am

    It worked!! Thanks!!

  3. Amelia Neblett said on November 6, 2010 at 4:41 pm

    Perfect content, well crafted I have to admit.

  4. Steve said on January 3, 2010 at 1:27 am

    Thanks so much for this! I’ve got a legitimate copy of both xp pro and vista pro, but neither were installed on the brand new hard drive that I want to put win7 on. Worked flawlessly. Thank!

  5. Jojo said on October 26, 2009 at 4:57 am

    OK, thanks Martin. This is another really stupid Microsoft policy!

    I suspect that their real goal in implementing this was to milk some more $$ out of their customers.

    If you do an upgrade on your old messed up system, it might work or it might not. If you want to ensure a better result by doing a clean install, then you’ll either need to buy a NEW full retail version or wipe your system, install a starter version of Windows and then install the upgrade you purchased.


  6. Jojo said on October 25, 2009 at 7:27 am

    “But what if you want to perform a clean install on a new computer system? The installation using the Windows 7 Upgrade DVD would work fine but it would not be possible to activate the operating system.”

    I don’t understand this! Is this a new policy in WIn7 from MS?

    When I did a clean install of XP, all I had to do during the install process was insert a CD of any earlier MS OS and there weren’t any problems. Will this method no longer work?

    1. Martin said on October 25, 2009 at 9:36 am

      Jojo, Microsoft has changed that. See or for details (Vista and 7 basically handle this the same way)

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