If its a maxtor or IBM drive its possible that it is set on one of its power saving modes, which caues the heads to load/unload during idle operation. This can make a 'funny' clicking noise. I used to think my IBM drives were really broken, but they were on powersave and I learned about head load/unload technology and it all made sense. I figured out how to put them into full power mode and everything was fine. maybe thats all it is. WD doesnt have fluid dynamic bearings...much less head load/unload!! so if thats what you have....RMA it now. Seagate doesnt use it either. Just maxtor and IBM. good luck