2004 Alero NEEDING HELP QUICK

I have a 2004 Alero that I just bought used about a week ago. Everything has been running fine until 2 days ago..it would not start. I waited a few minutes then it started right up. Today as I am coming up the highway everything dies...ALL power to the car is gone and I coasted into a parking lot. Approximately 15 minutes my husband gets into it and it starts. The code reading machine at O'reilley's says I have an evap leak but that it would not cause the car to immediately stall like that. Does anyone have any ideas about what it could be? Your help is greatly appreciated

So you are losing ALL electrical power? It's not just stalling? The car is completely dead, no lights, radio, ect...

If its stalling, does it crank over and not start, or will it not crank over at all?

Remove the battery cables and check for corrosion and tightness......

The 2004 Alero I bought last year has done the same thing twice before but always restarted and everything was fine untill tonight. It's just like you turned the engine off, no power steering, lights and all stay on. This time it would not restart. I called my wife to get a ride, in the meantime she looks it up on the internet. She says turn the key to the first position and wait to see if the security light is blinking. Mine stayed on, she said wait a minute or two then put the car in neutral then try to start it. I tried to start in in neutral earlier but not sure of the key position ,wait time etc. This whole ordeal lasted about 45 min trying to start, it was like it was not getting gas. Well just as my ride pulled up the key idea worked and the car started! She said it maybe had something to do with the "pass lock"? Not sure what that is but it seems a little dangerous to stall in the middle of the highway without warning! I made it home, it is Friday the 13th by the way. I believe it must have something to do with the fuel pump. Thanks for any help.