FIX: Windows Vista Activation – Product Key in Use Reviewed by Momizat on . There are many reasons as to why your activation will not work on Windows Vista. To name a few, you have chosen an invalid way of installing Vista (You chose Cu There are many reasons as to why your activation will not work on Windows Vista. To name a few, you have chosen an invalid way of installing Vista (You chose Cu Rating:
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FIX: Windows Vista Activation – Product Key in Use

There are many reasons as to why your activation will not work on Windows Vista. To name a few, you have chosen an invalid way of installing Vista (You chose Custom instead of Upgrade) or you have ran the installation without typing in the Product Key.

Now when you get the prompt to activate Windows Vista, you get an error saying “Product Key already in use” – Do not fear, this does mean that Microsoft has given the same product key to someone else, it just means that the Product Key has already been registered on the server and therefore needs to be activated by Phone.

However before you proceed to activating over the phone, you need to do the following steps in order to de-register your product key and re-register it. Firstly we would need to open the command prompt with elevated permissions. Now it may be that you are locked out of your computer now, do not worry we can still access it. Here are two ways to access the command prompt with elevated permissions.

If you are locked out of your computer do the following steps:

  • Select the option to “Access my computer with reduced functionality“.
  • – This will bring up Internet Explorer only.

  • In the Address Bar at the top type in the following “C:\Windows\System32” and hit Enter.
  • – This will open up a folder with a bunch of files and folders.

  • Search for a FILE called cmd
  • – This file may also be called cmd.exe and please note that this file WILL be in here – If you can’t find it, look further down as you may only be looking at the folders list. As I said before this folder contains files and folders!

  • Right Click on this file and select “Run as Administrator
  • – You may be prompted to click “Continue” or “Cancle” – If so, click “Continue“. Now you will have a black box on your screen.

If you are not locked out yet go to the following location in your computer.

  • Click on Start
  • Click on All Programs
  • Click on Accessories
  • Search for Command Prompt
  • Right Click on this file and select “Run as Administrator
  • – You may be prompted to click “Continue” or “Cancle” – If so, click “Continue“. Now you will have a black box on your screen.

Once you have the command prompt up, you can start typing in the following commands to deregister and reregister your product key.

  • Type “SLMGR -UPK” (without the quote marks) and hit Enter
  • Type “SLMGR -REARM” (without the quote marks) and hit Enter
  • Now close this all down and restart your computer.

Once your computer has restarted the activation screen will reappear. It will prompt you for your Product Key – Start typing this in now. Please do note that your Windows Vista Product Key is not the same as your Microsoft Office Professional Product Key. At this point, one of two things may happen. One is that you might get an error saying the product key you are using is invalid for this type of installation – If so, it means you have installed Windows Vista incorrectly as I had mentioned in the start. Secondly it will accept the product key and still will not allow you to activate it – This is the part that you call the activations department.

Firstly unplug your computer from the internet if it is plugged in and restart your computer. There should be an option to use the “Automated Phone System” or “Show me other ways to activate” – Whatever it is, we need to activate it over the phone so look for one that leads to a phone activation.

When you get the number to call in your specific country for the activations department, you will first be prompted to use the Automated Phone system – DO NOT USE THIS, IT WILL JUST GIVE YOU THE SAME ERROR. Just keep typing in fake numbers until it prompts you to talk to a customer service representative. Once you have been put through to them, give them the nine sets of Installation ID numbers and they will give you your confirmation ID. DONE!

Hope this helps… If you have any questions please feel free to drop a comment 🙂

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Number of Entries : 73
  • Chiquitafis89

    Thanks alot

  • Charvibunty

    i have windows xp and the product says product key already in use please help

  • Anonymous

    I cant find the “Automated Phone System” option please help 🙁

  • this was very helpful, cheers

  • jaydee

    This doesn’t work!! I have no start button and try everything that was posted and nothing worked.

  • Dav

    Gret…Many thanks, worked great with the Automated Service!!! Whooooo-hooooo. RESPECT

  • Try doing this.

    Ctrl + Alt + Del – This will bring up the task manager.

    Click File -> New Task (Run)

    Type “explorer.exe” and hit OK. See if your Start menu comes up.

    If not, try accessing the computer in Safe Mode.

  • No start menu?

    I got to the step where it says, “If you are not locked out yet go to the following location in your computer.

    * Click on Start”

    This would be fine, however I have no idea how to get to the start menu. It isn’t there in the left bottom corner and it hasn’t been since I’ve acquired this problem. I’ve been accessing all my files through my email. In other words, how do I get into the start menu and on to accessories and so on?

  • Thanks for this fix.I also getting this problem with my activation.

  • otumiseng

    my sister ‘s laptopo is giving us a problem with the eactivation,we tried its product key,and it need us internet and we can only access it at school

  • Matt

    NOW I HAVE NO CONTROL PANEL, WTH?!?!?!?!?!?!?!?!?!?

  • Rob

    Need windows vista build 6000 product key, can you help ?

  • Rob

    Need windows tist+ build 6000 product key, can you help ?

  • Daggen

    I bought a laptop with a trial version of Microsoft Office 2007 already installed. I did not have the product key for Microsoft Office in order to activate it to the full version (it kept on saying that I had 25 more times to enter a product key, 24 times, etc…). I kept on using word/excel/powerpoint until I had opened them 25 times and had to use the programs with “reduced functionality”. Now I have obtained the product key, but the product key prompting window no longer appears when I open word/excel/powerpoint! Is there a way to bring up that prompting window again somehow so that I can enter my product key to get the full version?? thanks

  • jack

    just reinstall vista and put the origonal product key in???

    I dont know much about this stuff

  • leandra cuffy

    i am unable to access word excel and publisher on my computer since the product key on the cpu does not activate it can you please help

  • When you say it does not open what do you mean? Is there an error or nothing happens…

    I can’t recall if this step would work or not by try accessing your computer from Safemode…
    If you’re unsure how to access safemode do the following steps

    Restart the computer and as soon as it starts up, start tapping the F8 key until you get the advanced boot option… Select safemode and proceed… Then try the steps to see if you’re able to deregister your product key…

  • Anwar

    cmd.exe file does not open

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