Inventor Family: An Autodesk product failed to send the required value for SERIALNUM.

I am only posting this to share with the community.  After researching our Discussions Groups, QA and various technical gurus within Autodesk, there are 2 solutions to this problem.

An Autodesk product failed to send the required value for SERIALNUM.

1.  Toggle off .NET 3.5.1, reboot your computer, toggle back on .NET 3.5.1 and reboot your computer again. Then try to run Autodesk Inventor.  In Windows 7, this option can be found in Programs and Features > Turn Windows Features on or off.

2.   Backup, reformat and re-install your operating system.  Here is another deadly issue with a hail mary type of solution:

http://upandready.typepad.com/up_and_ready/2011/09/error-unable-to-run-autocad.html

Epilogue I

We recently got workaround solution for this problem!  You will need to create a new user account on the system and see if you can start your Inventor in that new account.  You may also reset your own account in Windows 7 as well.

1.  To reset a user account, you will need to copy your account profile on a network/backup drive then delete it.

C:\Users\YOUR-ACCOUNT-NAME

2.  Delete the User Profile in System Properties and log back in as yourself.

Epilogue II

You can also try to use a previous Windows Restore point to go back in time. You will then choose a date that you last recall when Autodesk Inventor was last working.

Thanks to Dan Kerby for sharing this tip with the community.