So you missed your activation CD Key for windows 7 and still clueless about that. You can find it easily without registering for the Windows 7 DVD again and searching over the net. In fact you can find the cd key of this version as well as few other versions of the Windows 7.Here is how to get through it -
1. Extract the Windows 7 ISO. It‟s a tough one because it‟s a UDF Format and you would be requiring external software like CDExtractor or ISoBuster to do the work.
2. In the DVD root folder there is a folder sources….open it.
3. Find a configuration file product.ini
4. Open this file
5.Scroll till the end and you can find number of various keys for versions like Ultimate, Professional, Starter and many more…