My Windows 7 product key won't verify. What's the problem?
The most common issue is the use of a product key for a product not currently supported by the site such as an Upgrade key, an MSDN key, product keys for pre-installed media or an Enterprise edition key. For access to MSDN products or Enterprise edition visit the MSDN Portal or the Volume Licensing Service Center. Upgrades and pre-installed media are not currently supported by the tools on the site.
If you believe you have a valid product key and are still receiving an error, please contact Support.