User profile synchronisation service wouldn't start - cert issue

UPS has been offline for a few days now.  There was an error message about certificate couldn't be issues so I searched on google and found a few articles about deleting the forefront certificates and try to restart the service.

I've decided to delete all forefront related certificates on the server that runs UPS and tried to start the services.  User profile synchronisation service started but user profile service was trying to start but stopped.  A number of forefront certificates were created also.

Can anyone suggest some ideas please?