We have a laptop that has an OEM copy of Windows Vista. Somehow the OS got corrupted and the only restore option is a recovery partition that also seems to be corrupted. We have verified that the hardware is fine, and the problem is purely software.

If we buy a Windows 7 Upgrade license, can we do a fresh install without a working Vista install? How does the upgrade know if I have a copy of Vista?

  • 1
    Spend the extra $100 and get a full retail version, which can be transferred to new HW in the future. OEM upgrades are tied to the OEM machine that was upgraded. Jan 26, 2011 at 2:04

4 Answers 4


How does the upgrade know if I have a copy of Vista?

Older versions of Windows allowed you to insert the old CD into the drive; Vista/7 don't allow you to do this. You need a copy of Windows already installed on the drive before upgrading. Of course, you can wipe the drive after it validates and allows you to start partitioning. (Just don't restart!)

If we buy a Windows 7 Upgrade license, can we do a fresh install without a working Vista install?

In short, it depends on how corrupted the install is. Nobody really knows what Microsoft checks in its upgrade process; it's a secret.

On what you can do if this doesn't work:

Warning: IANAL, this is likely against Microsoft's EULA, but I consider it ethical if the OEM install is corrupted and will not install normally (always try the definitely legal way first ;)).

You can use the Windows 7 upgrade trick to install Windows 7 without a clean install disk: http://www.pcworld.com/article/174288/windows_7_upgrade_made_cheaper.html

Basically, install Windows with the Upgrade disk (don't worry if it doesn't validate), use slmgr -rearm to rearm the system (making it look like it's validated for up to 120 days (which is why this is not a permanent solution)) then install Windows AGAIN from the upgrade disk. It should recognize the "upgrade" install, and allow you to install a permanently validated version.

  • Why the downvotes? I haven't tested the solution but it sounds like a pretty clever work around. Jan 26, 2011 at 1:46

You can't do a fresh install with a Win7 Upgrade license (the name said it all). You will need a full license to install from scratch.


When I bought Vista, I got an upgrade copy and installed it on a fresh VM that has never seen Windows before. I don't know if Windows 7 is different.

If the hard drive is corrupted, what's the harm in trying? If it refuses to install the computer will neither work better nor worse than before.


The following method is similar to Hello71's reply above, but doesn't require the second install of Windows 7, so it should be much faster.

  1. From the command prompt or start menu, type regedit to start the registry editor, then navigate to the following location within the registry: HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE
  2. Change the MediaBootInstall key from 1 to 0
  3. From the command prompt, type slmgr /rearm and wait for the confirmation dialog box.
  4. Reboot your computer and activate normally.

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