You can not just click it, it needs to know at least the config file with -c parameter.
First check /ProgramData/Repetier-Server/logs/server.log if it contains any information. There it will log what it does. If that does not work try starting by hand in command line interface.
If it still does not work I guess there is an issue with you data directory. Try renaming /ProgramData/Repetier-Server and start. Then you can copy parts back until it stops starting. That way you find what is preventing the restart. Then report back so we can fix that problem maybe (if it is not a defect database file).
