Key FOB problem- common?

[Jojo]

Hi all, so I came out of my 2003 Boxster S and needed to open again the car with the key fob, but the remote will not respond, and noticed that the red LED was flashing slowly, as in once per second and not like another working key fob I have, which flashes faster when pressed.

I've tried all I've read on this forum, as in key in ignition on, key out and press etc, but all to no avail.

I was wondering whether actually this key really needs to be re programmed at the Porsche garage? or maybe there is a way that I can make it 'talk' to the car myself?

As I said, the other key fob i have works fine with the car, and i also replaced the battery with a new one just in case.

Thanks

Jojo