RepairPal Certified shops can diagnose and repair your 2002 Porsche Boxster. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
First try using the manual key on the driver door. Lock and unlock a few times and see if your alarm goes off. Provided that's your issue. If that doesn't work than you can disconnect the alarm module under the driver seat.
Alex