Travelling at 70 miles per hour our 97 Volvo 850 GLE wagon lost power--lights went out and engine shut off. Luckily we were on the right-hand side of the interstate and could still steer. We got off on the shoulder. It restated with a little difficulty and continued with no further problems. About a month ago we had the alternator checked at the dealer. It could have suddenly gone bad in the last few weeks, but I am skeptical about that. At that time we had the dealer replace the battery. The problem seems electrical in nature. Any ideas as to the cause would be much appreciated!