You probably have corrupt settings data. Since this is ready before WWT code can run, if it is corrupt, Windows will prevent WWT from running and there is nothing WWT code can do about it.
You can reset your config files by deleting all the folders that begin with "WWT" under c:\usrs\{your username here}\AppData\Local\Microsoft_Research
Be careful not to delete anything else by accident.
This should revive you running.
This condition can happen if Windows shuts down too quickly while WWT is running. If the WWT process is killed by windows while the .net Framework is writing the settings file, it can become corrupt.