HI I HAD THE SAME PROBLEM, GREEN LIGhT ON BUT NOT SWITCHING ON.
I contacted tomtom and with in 2 weeks i have my original 910 back in full working order. AND I DIDN'T COST ME A PENNY.
My tomtom was an insurance replacement due to stupid little thieves,
but i didn't have any form of a receipt. I contacted free and they went
through the normal try resetting the device BUT HOLD DOWN THE RESET
BUTTON FOR 30 SECONDS NOT THE 15 THEY STATE IN THEIR HELP SECTION. Done
that and it DID SWITCH ON only for a about 1 min due to the battery not
holding its charge. So they sent me all the packaging to return it to
them, did ask that i put proof of purchase in but couldn't so just
wrote a quick not saying insurance replacement but checked when i
activated my device on my computer it was july 2006 so expected to a
repair fee thinking it only had 1 years warranty but if you brought
after Jan 2005 it has a 2 year warranty. Received it back today full
working order and the battery replaced.
Worth contacting TOMTOM number is on www.tomtom.com/368
Hope this helps.
if that doesnt work and u need to replace the battery... there is electronic cards one is two screw remove that and second
one has four screw remve all and remove the sockets than you remove two
more screws from under that after remove battery carefully this is
little bit diffucult be carefull
please check out the disassmebly instructions in the below link...
A very helpful rating is appreciated for responding to your