How does Microsoft identify the computers hardware? Can hardware components be changed?

Microsoft Product Activation detects the hardware configuration on which the product is being installed and creates a hash value for that configuration. A hash is a value mathematically derived from another value. Product Activation does not scan the customers hard drive, detect any personal information, or determine the make, model or manufacturer of the PC or its components. Microsoft uses hash values in order to protect users privacy. Together, these hash values become the complete hardware hash that is included in the installation ID. By using this type of hash, Product Activation is able to tolerate a certain degree of change in a hardware configuration. As a result, users can change their hardware without the product believing it is on a different PC than the one it was activated on. If the user completely overhauls the hardware, reactivation may be required. In that case, users will need to contact to contact a Microsoft customer service representative by telephone to ...  more