on Saturday I was driving my car and it just turn off. I was trying ot turn it back on but it didn't. I kno its not the fuel pump, when I turn the key I can hear the pump turn on. I took it to the mechanic a day before. He replace the brake booster. Thanx

 

Just because you can hear it come on, doesn't mean its not dead, I would first check that the brake booster hose hasn't pulled off the booster or the intake manifold, if that checks out, I would check the other vac hoses.
When it died, was it immediate, or did it cough and sputter, or drop RPMs? And at what speed were you going, or was it at idle??
But best place to start after checking for a vac leak, get some starter fluid and spray it down the TB mouth, if it starts then you probably have a fuel issue, if not most likely an ignition issue, on an engine with no known likely cause to stop working, its usually fuel or spark, or ignition timing. Could also be a blown fuse, does it turn over still? Could really use some more info....

 

First of all tahnx for the help. Ill check that in the morning. I was going around 40 when it just turned off. I couldn't hear nothing I had the music loud