Windows 7, the latest operating system from Microsoft needs a product key to get activated. However, you can use Windows 7 trail versions as evaluation copy until it expires but then you need to purchase a valid product key to activate Windows 7. Microsoft has introduced genuine product keys for each copy of Windows 7 which is 25 characters long and unique. Once you enter the product key, your system checks for the edition of the Windows, features to unlock and activate, license type and unique identifier to determine if activation should be accepted.
There are separate identification characteristics embedded in a each and every number of a product key. Microsoft keeps the track of each and every product key using pidgenx.dll file along with pkeyconfig.xrm-ms. Microsoft also uses these files to validate or blacklist a product key during initial installation when there is no Internet connection available.
By understanding the product key database and algorithm in pidgenx.dll, few developers have developed small programs to check the license channel or type, edition with many other informations of the Windows product key. Two of these programs are Microsoft PIDX Check and Windows 7 product Key Checker.
Microsoft PIDX Check
Sources say that it’s probably the first and original product key checker. Microsoft PIDX Check has been used to make a lots of working one-click activation cracks for Windows vista. It can retrieve several informations from your system such as PID (Product ID), ID1, ID2, Type, Subtype, Class and Crypto ID of the product key.
Windows 7 RTM release is one example of this program. You can download Microsoft PIDX Check here.
Windows 7 product Key Checker
Windows Product Key Checker has been developed by a Russian programmer and this version has got updated for Windows 7 RTM. This tool also has enhanced on graphical user interface, with full description of the every fields of the product key, namely Product ID, Extended PID, Activation ID, Edition ID, License Type, License Channel, and Crypto ID.
You can download Windows 7 Product Key Checker here.