Yes you can if the battery is the problem. connect the red on car with good battery to the positive ( + ) terminal, then the red on the dead battery, connect the black to the negative ( - ) on the good battery and the black to a good chassis ground( exposed metal in engine bay ) a good spot is the strut mount bolt.
On a Passat, the battery is located under the hood. It is under the cowl panel and requires the removal of the battery cover to see it.
try to disconnect the battery for an hour and then connect it back on. solved my problem.
No it will not restart
Use a cable and software from VAGCOM.
Here's what I used for my 2006 Passat: http://forums.vwvortex.com/zerothread?id=3334037
On the 2006 passat it is under the hood in the battery box. On some passats it is located in the trunk on the left side (US driver) behind a cosmetic panel.
Next to the firewall in the engine compartment.
By the firewall (far back, center), simply slide the battery cover to reveal the actual battery.
Use your key to unlock the door.
go to radio shack