My 2000 jag ran fine let it sit 3 weeks tried to start seemed battery was dead.I could turn switch key to crank and the

Customer: my 2000 jag ran fine let it sit 3 weeks tried to start seemed battery was dead.I could turn switch key to crank and the horn blows and it clicks at under hood fuse box at trunk and on passenger side of car inside.I did jump the car off before this happened and it started but the key would not turn the car off.can you tell me whats wrong.my name is*****: Did you test the battery with a voltmeter? And have you ever changed one before?
Customer: no for both
JA: What is the model of your '00 Jaguar?
Customer: s type
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: im going to try.I am charging the battery out of the car and make sure it has full charge.I am going to reinstall and see if key will start.if I turned the switch on before the gauges would run up and down and car didnt start.
JA: Anything else you want the mechanic to know before I connect you?
Customer: if i replace the ignition switch from used jag will the new key with used switch will anything need to be reprogramed