FIM Sync service not starting

I am getting the following error when trying to start the FIM sync service:-

Windows could not start the Forefront Identity Manager Synchronization Service service on Local Computer.Error 5: Access is denied.

And this is what in application logs:-

The server encountered an unexpected error and stopped.

"BAIL: MMS(5472): d:\bt\800\private\source\miis\server\server\service.cpp(2260): 0x80070005 (Access is denied.)

BAIL: MMS(5472): d:\bt\800\private\source\miis\server\server\service.cpp(1088): 0x80070005 (Access is denied.)

Forefront Identity Manager 4.1.3419.0"

Any HELP please.....

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