How do you open froont hood on Porsche boxter 2003 when battery is dead?

Assuming you haven't already tried the keyfob button, and it didn't work....

Go inside the car, and remove the cover of the fusebox which is located below the steering column near the floor, and you should see a fuse that has a picture of a car with the front trunk open, pull on the fuse and it should come out, BUT NOT ENTIRELY, then attach the positive jumper to the outer edges of the fuse (where the metal is) and the trunk should open.