OK, most of us have received or bought a used computer before. If the computer comes with a hard drive loaded with Windows, chances are you probably want to erase the contents on the hard drive and perform a clean install. In most cases, you probably won’t get the original product key needed in order to install Windows. These keys are important especially for Windows XP and above since they require product activation and cannot accept a product key already used by another computer. However, there are some ways to retrieve the original product keys before you erase your hard drive.

Windows 95/98/ME

  1. Locate the product key by clicking on Start and selecting Run.
  2. In the run box, type regedit. (While in regedit, do not make any changes!)
  3. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion.
  4. In the right column, look for ProductKey. The product key will be listed to the right.

Windows XP/Vista/7
Microsoft got smart and hid the product keys in these versions of Windows, so the above procedure will not work. You can, however, download the Magical Jellybean Keyfinder or the Belarc Advisor in order to retrieve the product keys.

Some things to remember:
Recovery discs from a computer manufacture usually don’t prompt for a product key. However, if you’re recovering a computer with a version of Windows prior to XP, you may be asked for a product key.

Before erasing the hard drive and performing a clean install, check the systems properties to verify if Windows is a retail version or OEM.  This is important as OEM copies of Windows setup disc will not accept retail product keys and vice versa.