My wife used our Garmin Nuvi 750 last night, when she put in a location to find today. This morning the unit would not power up (dead), also will not power up when attached to cigarette lighter power adapter, and will not connect to computer using usb connection. Is this unit repairable? Thanks

I am unsure of your particular device, however consider the following.

Like many electronic devices, (such as computers and cell phones) often units when the battery is dead flat will not start up for an extended period, even when attached to a power source. GPS units can be extremely temperamental to charge with a cigarette lighter charger or computer connected USB charger when the battery to the GPS unit is dead flat, even with genuine manufacturer supplied chargers.

Perhaps try to use a wall powered charger on the device. Give the unit a good couple of hours to charge correctly.

My Navman when switched on for example, will still slowly go flat with the genuine factory supplied car charger on and eventually the screen flickers, the unit will stay on but switches off as soon as ignition is off. When I start the car again the unit will not flash up again for atleast ten minutes. Car chargers for these type of devices can be extremely poor in their capacity to charge, particularly when batteries are dead flat.

No! you are further ahead replacing the unit.