Recently after working one day the next day when i tried to use mt tom tom 710 it wouldnt switch on but the mains light was lit when plugged into cig lighter

What did you plug in? I had a similar issue when I plugged in a high amp tire pump. It kept blowing fuses because the pump itself had a short. Be wary of using stuff like that in the cig lighter. I switched to a hand held pump. How was the computer found to be defective? I wonder if the cig issue shorted the computer?

I have had the same problem. unfortunately I have been told that it is the cradle connections to the main unit. they are at fault due to wear and tear and causes the shutdown. Try wiggling the cradle when connected, if there is some slack play then you may also have the same problem.... by the way, Tom Tom are not interested unless within warranty and they dont sell replacement cradles!

Try these 3 things - wait at least 20 seconds before trying the next step:
* Reset the device, you may need to use a paper clip to do this, then try the power switch.
* Remove the SD card and re-insert it, then try the power switch
* Hold down the power button for about 5 seconds.

it doesnt get better by itself. Despite having a green light doesnt mean it is charged. try changing the battery

if it does not proceed when the icon is selected, presume data corruption or in fact no data.
TomTom is renouned for this type of problem.
try rteinstalling the map data from the source.

try a reset first ( small pinhole on rear) put open paperclip end in and gently push the button inside) if this still fails then data installation is the go

Change the motherboard, green light on and nothing happening is quite common, you can find motherboards on ebay for £22 +p&p.

Its quite easy to do and worth while as the 710 and 910 are still very good units.

when starting the vehicle, the unit gets a surge. disconnect before starting the car. If it has a cig lighter power adapter, it was not meant to stay plugged in 24-7

not sure but try an other device on the car plug to see if it works??????????? could be the plug.

Please try a reset:
http://www.tomtom.com/support/index.php?Language=4&query=reset&FID=7134

Go to tomtom website and look under support. you will find all the manuals for every version.