Windows 7 Professional OEM Key SP1

If you encounter any issues during activation, please follow these steps:

Open Start menu, type SLUI 04 and press enter,
Choose “Use the automated phone system”,
Select your country, and call the toll-free number. Follow the instructions provided by the automated activation system to receive a confirmation ID and activate your OS.

You can also click here to check out an illustrated guide of this activation method.Click on the desired system version to visit the 3rd party download site: Ultimate / Professional / Home Premium / Home Basic