Boxster S Alarm keeps on going off!!!

[Overdrive]

Check to be sure your ceneter console lid is indeed closed. It may look it and not actually be secure.

Also, do you still have your stock radio? If you've changed that out to an after market head unit, there's a grounding strip on the back of the stock unit that grounds out to a wire in the console. If you lose that contact, the car thinks the radio has been removed by thieves/vandals/rapscallions and wil sound the alarm. If you have replaced the radio with an aftermarket, you'll want to resolve that issue. If you haven't, check it anyways, as the contact or wire may have built up some corrosion and lost the ocntact.