Ask LH: How Can I Find My Windows Product Key?

Dear Lifehacker, I have a question regarding Windows 7 Home Premium. I bought it and installed it on my laptop about four years ago. A few weeks ago I experienced some technical problems with my browser and had to reboot my laptop and reinstall the OS. However, I can't use the Internet anymore because my new installation hasn't been authorised. Unfortunately I don't have my product key any more. What can I do? Can I purchase a new discounted product key or am I stuck with buying a whole new copy? Thanks, Locked Out

Dear LO,

The issue you've got isn't an uncommon one, and unfortunately it's not one that's likely to end cheaply for you.

The first step I'd advise would be to call Microsoft and explain the situation.

Any supporting documentation you have that could verify your previous installation (like, for example records of previous calls to Microsoft or emails verifying details) may help in convincing them of your bona fides, and they may be sympathetic and provide you with an authorisation key.

Failing that, however, you're probably stuck with buying a new copy. The lesson for everyone else? Remember to use tools like Magical Jelly Bean Key Finder to verify your keys before any future fresh installs.

Cheers Lifehacker

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    There are 2 options that I use.
    1] Speccy
    Speccy is a small footprint but advanced System Information tool for your PC from Piriform - a well known and trusted source of software.

    2]Belarc Advisor
    If you want to get down and dirty then this is the better option. The Belarc Advisor builds a detailed profile of your installed software and hardware, network inventory, missing Microsoft hotfixes, anti-virus status, security benchmarks, and displays the results in your Web browser. All of your PC profile information is kept private on your PC and is not sent to any web server.

    If you still have a windows.old folder in C:\ you could use produkey from to browse the old registry for keys.

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