Ensure the vendor provides a buyer protection guarantee and concrete customer support channels. 3. Volume Licensing Service Center (VLSC)

You can validate your 25-character product key using either the graphical interface or the command-line utility. Method 1: PC Settings (GUI)

Activating Windows 8.1 Pro is essential for several reasons:

The key is invalid, blacklisted by Microsoft, or has exceeded its maximum activation limit. System clock mismatch

Install your fresh product key by typing: slmgr.vbs /ipk XXXXX-XXXXX-XXXXX-XXXXX-XXXXX

Swipe in from the right edge of the screen or press Win + C to open the . Click on Settings and select Change PC settings . Choose Activate Windows (or PC and devices > PC info ). Enter your 25-character key: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX . Click Next to initiate the online validation process. Method 2: Command Prompt (SLMGR)