Activation problem and do not open inventor

Have anyone been in this situation please help. Today when I restarted my computer and tried to open inventor which I am using for few months now. The strangest thing happened to me and it gives me the activation error and fails to start. I even tried to access my files through the vault but the same error persists.
One thing that struck to my mind was to clear or edit the registry for this application. So, I jumped into the regedit but there is no registry value entry on local computer registry for this application. Please help me with some valid solution. Here is the screen shot of the error:
