I have a 1996 XK8 convertible that is used a couple of times a week. My car has locked itself (home in the garage fortunately). When I try to unlock it with either the remote or the key, the car alarm starts going off. I was able to unlock the trunk with the key and disconnect the battery and the alarm stopped.
My problem is what to do to fix this problem and any suggestions would be appreciated.

 

You might get better/more accurate advice from the XK8 forum than the XJ8 forum...

On my XJR, inserting the key in the ignition will silence the alarm if I've inadvertently triggered it.

 

Check the battery voltage and recharge if low (below 12V is no good). Some alarms go "crazy" when the battery is signifficantly discharged.