Prob w/ 1999.5 Pathfinder that Nissan can't figure out?

[altygirl]

I have a 1999.5 with a big prob. I turned off the car the other day and the thing went completely dead when I tried to lock it from the inside. It then made a beeping noise and would not turn back on. I took it to nissan and then can't figure it out. Has anyone ever had this prob???? And knows how to fix it???? I just go a new key made and new remotes for the keyless entry, could this be the prob??? Help please I have less than two weeks to figure this out before I an completely stuck with this car......