This question is about win7, not an OEM license. I'm planning on getting windows 7 home basic for my machine. However, I'm also planning on building a PC in the next year or two.

Now, I've read around here that a single license can be installed on multiple computers, as long as you don't use it on two at the same time. Thing is: when I get the OS installed on the PC I'm gonna build, I'm gonna want to transfer a lot of stuff from one machine to the other. I'd like to do this through a local network, I don't have an external drive large enough to perform the transfer.

Since I'm gonna have the same license installed on both PCs, and since I'm gonna need them both running simultaneously for the transfer, I need to know how does the limitation actually work:

  • Is it only a legal matter? (it would be wrong to use both at the same time)
  • Is it also a windows update limitation? (once the second PC gets activated, the first one no longer has access to windows update)
  • Is it a stronger limitation? (once the second PC gets ativated, the first one will detect it during boot and just stop working)
  • Is it something else?

(The first two options wouldn't be much of a problem, since I'm only gonna use the old one for a few hours. The third option, however, could mean a headache.)

(Update: I've decided I'm either gonna transfer the HD itself to the new machine or set up a local network before activating the second machine. So my problem is solved.)

  • you should discuss this with an attorney at law specialized in the matter, the legal aspects are different in most contries. in many countries the EULA is not legally binding, but Microsoft can and will push the killswitch as they see fit. SU is a place to ask for help with technical not legal problems.
    – Molly7244
    Nov 24, 2009 at 19:01
  • @Molly: I'm more worried about the software side of this. I understand and abide the legal side: I should only use the same license on a second PC if I no longer use the first one. What I want to know is how is this verification made, and how do I know my second installation won't be suddenly blocked by the software.
    – Malabarba
    Nov 24, 2009 at 19:17
  • there are ways to backup and restore the Windows 7 activation files (which might be illegal), in the end you are the mercy of Microsoft, because they are the guys with the finger on the killswitch and if they smell a rat (e.g. tampering with the activation), your license might be revoked. you want to play it safe, then play it by their rules.
    – Molly7244
    Nov 24, 2009 at 20:05
  • @Molly7244, The fees you need to "discuss" with an attorney is enough to buy you more than just several brand new computers.
    – Pacerier
    Oct 24, 2015 at 1:08

3 Answers 3


An OEM licence can only be used on one computer and only one computer - it can be reactivated as many times as you like, but again, only used on one single computer and not transferred.

A Windows Fully boxed product can be installed on as many machines as you like as long as it is only one at a time.

On all of these, if you do it to much, activation will fail however it is just a matter of ringing up Microsoft and explaining the situation, they will either give you a code to type that will activate Windows or give you a new key.

To your points.

  1. Yes, really just a legal point.
  2. No, Windows update will continue to work on both.
  3. No, and even if it did, Microsoft have weakened the security, worst case scenario is you have a 15 second wait at start and no desktop wallpaper.
  4. Not really.

However, if you have a new pc and just want to transfer files, Personally, I would put the hard drive of the old one either in an enclosure or just connect it directly to the machine.

  • 1
    Yes, but even a non-OEM can't be installed on multiple machines simultaneously. Also, have you ever had to ring up microsoft to get a new activation key? Not fun. Nov 24, 2009 at 17:42
  • I agree, but look at number one... I said that it should work fine and it is really just a legal point. Nov 24, 2009 at 17:43
  • 3
    "Personally, I would put the hard drive of the old one either in an enclosure or just connect it directly to the machine." +1
    – JMD
    Nov 24, 2009 at 18:11
  • I like the hard drive idea, and I'm probably gonna do that. But other answers seem to disagree with yours, are you positive about your answer?
    – Malabarba
    Nov 24, 2009 at 18:45
  • 3
    I have called the activation line...it was easy--no big deal. Nov 24, 2009 at 18:55

You don't have to activate your second computer right away. It will work for several days before the OS requires you to activate it. I don't even think you're required to type in your product key right away. Just click 'continue' when asked for it.

Just transfer all your files, then turn the first computer off, then activate your new one.

  • Good and simple, if the old hard drive isn't compatible with the new PC, I'll just do this then. Thanks
    – Malabarba
    Nov 24, 2009 at 18:52
  • ALso, if you do activate the new PC immediately, your old one will enter the trial/non-genuine period and will still be usable for at least 30 days.
    – jiggunjer
    Jan 14, 2016 at 5:14

Check out the wikipedia Windows Genuine Advantage page and this Microsoft social.answers page. It explains that you should still be able to receive security updates on both machines. You may start getting pop up boxes about your machine not being 'genuine'. However, question #5 on the social page is interesting:

From what I've read about the program that verifies you have a legal version of Windows running, Windows Genuine Advantage (WGA), it collects the activation key from your computer and compares it to all the other computers running Windows. If it finds that two computers are using the same key it concludes both are not genuine it can shut down Windows in some way on both machines. So - if you legally move your Windows 7 upgrade install from one computer to another and WGA collects your key and finds it's being used on a different computer what keeps it from shutting down your computer? How will it know it's still a legal install? And in this and the questions above what happens if WGA falsely determines your installation is not legal even though it's only on one computer at a time?

The Microsoft MVP answer:

The first install takes presidence[sic] till a phone call adjusts that.

The Windows Genuine Advantage FAQ is pretty blunt:

Windows is licensed for use on a single PC and can not be shared among multiple PCs. If you receive a copy of Windows pre-loaded on your PC, you can not transfer the license to another PC.

  • "The first install takes presidence[sic] till a phone call adjusts that." Does that mean i have to call Microsoft and transfer presidence to another PC or i just need to deactivate first PC so Microsoft's staff will delete license registration from Microsoft's database?
    – Boris_yo
    Jun 4, 2011 at 7:22
  • "it can shut down Windows in some way" - have you ever seen this?
    – user162573
    Oct 5, 2014 at 21:31
  • Sure it's written by an MVP, but no matter how you look at it, "The first install takes presidence till a phone call adjusts that" isn't authoritative at all.
    – Pacerier
    Oct 24, 2015 at 1:15

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