1999 boxster won't start

[other.issues]

The car was running fine until one day, the engine started to trun on and then went dead. Now, there is a clicking sound when I turn the key, the lights/radio etc. all come on but the engine won't start. I've had the starter and the battery replaced but no luck. The mechanic thinks I might have to replace the entire motor. Could it be anything else? Help! There wer eno warning sign - not check engine light, nothing.