My car died -- and I'm no mechanic. I barely understand the basics of car engines. So I need some help diagnosing what's wrong. The battery needed to be replaced; it's voltage was at 10.2v instead of 12v. It also needs an oil change. But that shouldn't have caused this. The only other factor that I know about is I normally let my car engine run for 10 minutes before driving in the winter; today I didn't. Otherwise, the car has been driving normally for a while. I've been thinking I noticed a loss of power over time -- slower acceleration type of thing -- but I thought it was in my head. So today I leave my driveway, radio on, headlights on, and start driving. Less than a mile down the road, I go to make a left and I notice my car won't accelerate when I hit the gas. So I go into the turn anyway, I have enough speed I can at least make it to the shoulder. My power steering is gone. I make the turn, straighten out, and there's still no acceleration. Pumping the gas pedal does nothing. Luckily I make it (barely) into a parking lot. Turn the car off, count to 25, try it again -- doesn't even try to turn over. My wiper blades go, but slowly; the radio works fine, as do my headlights. With my little knowledge of cars, I believe the battery to be virtually dead and the alternator to be trash. However, I don't know if a dead battery and alternator will cause a car to stop running in the middle. And how do I test an alternator?