My car won't start- the engine won't turn over- on 2000 Jaguar XJ8

the car has been siting for a while- the battery when boosted lights come on..but the starter just clicks...

Asked by for the 2000 Jaguar XJ8
Replace the battery!! Might try charging it for about 8hrs at 6 amps. If it sat during COLD weather then battery is shot as that fluid stuff inside becomes water after charge is gone. Water freezes, battery plates warp!