A. Validation is an online process that verifies that your copy of Windows is genuine and that critical Windows licensing files have not been damaged, deleted, or removed. It takes only a few moments and lets Microsoft create a match between your PC's hardware profile and your 25-character product key, which is usually located on the Certificate of Authenticity (COA). This match is anonymously archived so it can be checked against future activation and validation attempts and helps make sure that the Windows product key installed on your PC matches the original Windows product key that was purchased. In this way, validation helps ensure that your product key is not used by another person in a malicious manner, such as activating a counterfeit or non-genuine copy of Windows. Microsoft might ask you to validate after Windows activation, when you request a genuine Windows download from the Microsoft Download Center, or when requesting a non-security-related download from Windows Update. No personally identifiable information is collected during validation.