Help I've disconnected the battery and closed the bonnet
 

I've tried powering via the red fuse in the fuse box and earth but nothing happens. Any ideas please

You can apply 12V to the cigarette lighter socket and then use the button to open, good luck!

I believe that under the front bumper cover there is a wire cord you can pull that will manually open it..if you have the manual available I think it shows where its located..Good Luck !

When you say you applied power, I'm not sure what exactly you did but...
I never had luck with a battery charger connected to the post in the fuse box.
I always had luck with a battery and jumper cables connected from one of my other cars.

Not sure...do the electrical approaches to this problem still work if the battery is totally disconnected? Ie, there's no longer any complete circuit? Maybe, I don't know..

In any case, if you need to do the mechanical approach, this will give some guidance..

http://986forum.com/forums/boxster-general-discussions/63915-help-disconnected-battery-closed-hood-jumper-method-doesnt-work.html

In theory it should still work. The battery cables only complete the circuit with the battery. If you connect an external power source to the fuse box terminal and a good ground, then you'll have a complete circuit to that external power. I'm guessing the real question is how many amps does the release solenoid draw? Dghii said he had good luck with another car battery, but not with a charger. Maybe the charger he used charger can't handle the draw from the solenoid. My guess is that it may draw around 5 amps.

I had to do this once. Battery charger wouldn’t do it. Jumper cables did the trick.

Remove the front, right wheel. Remove the plastic fender liner. Look around the rear of the right headlight fixture for a bare cable with a loop in the end. Pull on that and it should pop the hood/bonnet.

https://youtu.be/9o3X7DaHrxw

Note: You can apply the 12V using jumper cables connected to a cigarette lighter plug Not with a battery charger

Trunk cable release
 

Attachment 23414

In the attached PDF, item 12 is the cable accessible from the right side wheel well after you remove the liner. If you do this you may want to reroute the cable so you van grab it from the front of the car through the grill.

This is how I opened my 2000 S