How to install and activate Windows 11 with a product key
Updated November 1, 2026
Whether you're upgrading an existing PC or installing on a new drive, the process takes about an hour. All downloads come directly from Microsoft.
Before you start
- Back up your files to an external drive or cloud storage.
- Run Microsoft's PC Health Check to confirm TPM 2.0, Secure Boot and processor support.
- Have your 25-character product key from your order message ready.
- For a clean install, have a USB flash drive of at least 8 GB.
Activate an existing installation
- Open Settings > System > Activation.
- Select Change product key.
- Type the 25-character key and select Next.
- Wait for the confirmation that Windows is activated.
Clean install from USB
- On a working PC, open Microsoft's Windows 11 download page and run the Media Creation Tool.
- Choose Create installation media and select your USB drive.
- Restart the target PC and boot from the USB drive (often F12, F11 or Esc at startup).
- Choose language and keyboard, then select Install now.
- Enter your product key when asked, or select I don't have a product key and activate after setup.
- Choose Custom install, select the drive, and follow the prompts.
If activation fails
Make sure the installed edition matches your key: a Pro key won't activate Home, and vice versa. Open Settings > System > Activation > Troubleshoot. If an error code remains, send it to our support team with your order number.
