Electrical Issues....Need Help!
 

I have a 1994 Regal GS w/3.8. Last week I had a new alternator installed. Car driven daily and had run fine since the new alternator. Tried to start yesterday after work and car was totally dead. Wouldn't crank...no radio, power locks, window...anything. Tried to jump start the battery and got nothing...totally dead. In the process of taking out the battery to get tested I noticed that the dome light under the hood would flash on and off as I would turn the bolt on the positive battery terminal. When the light stayed on I tried to start the car and it fired right up like nothing was wrong. I let it idle for about 10min. When I went to drive it home....I turned on the defog and the car turned off. Now it is totally dead again. I thought it was a dead battery but now i think maybe a short or ground issue but not sure. Any advice would be appreciated. Thanks.

First I would recheck both battery cable connections at the battery, positive and negative. Cars don't just shut down like you describe except for a catastrophic failure which would occur when battery supply is lost. Lets see if you find any corrosion under those battery terminals and make sure they are clean and tight. They can be cleaned with a baking soda solution.