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I have just recently bought a windows 7 os to upgrade from windows vista and I installed it and it worked. A few years later I used up the disk (3 times) and when I installed it on the fourth computer it said the key was not valid. I understand that you can use it on only three computers but is it possible to use it on more

Ps. Tomorrow is that if you contact Microsoft, and give them your key you MAY be able to use the disk on three more computers

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You can use the disk on as many systems as you like. Your key is only licensed to be used on 3 installs, and you shouldn't be able to use it on any more systems. In some cases you can transfer the license, or get the license key authentication approved for systems that have been modified enough that they can't tell its the same system. This will not add additional licences for you to install however - you're not supposed to be running installs with that key on more than 3 systems.

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Ok that's what i figured because they will give you thirty days to put a license in and it will disable the features after that but I googled it and it said that if you contact Microsoft they could give you three more uses – Hunter Mar 29 '13 at 7:35
Yes, but even those extra uses will not legally entitle you to simultaneously use the same key on multiple PCs. Be careful or you could end up with the key getting blacklisted. – Karan Mar 29 '13 at 8:54
Yup. This is a very bad idea, since you could end up with 0 licences instead of 3 more. You absafragginglutely do not want to do this. – Journeyman Geek Mar 29 '13 at 23:53

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