How do I replace the battery.

Thank you very much,I will keep you informed about how I go!

you're welcome ;-)

I have replaced the battery without any obvious problems, however my 720 will not open beyond the “connect to computer screen”. All files appear to be still in the unit, it just wont fire up. What have I done??

edward, good job on replacing the battery. Have you tried to reset your 720. The reset on the bottom of the device forces a hard restart of the device, and does not otherwise change the contents. Also, of course, you checked and double checked your work to make sure that everything is connected the way it is supposed to.

Hello again, Yes all was double checked so I’m confident it is back together properly. When I connect it to my computer it works perfectly with all memory functions, favourites and previous input and settings working perfectly, its when I disconnect from Tom Tom Home and try to use the unit it wont go beyond the start screen. Looking on the net it seems a common problem to some owners, it just seems like its missing a link to kick start the program. Obviously all the files required are in the hard drive but something happened when the battery was disconnected.