Car Problem (Technical)

I left my car unlocked and some of my friends did something to my car to make it not start. The dash lights and the headlghts turn on, but nothing works, and when I start it nothing happens. It is a 2001 Mustang. Please help, I can't get ahold of who did it and I don't know how to fix it. I'm sure it is not something unfixable.

When you say it won't start, are you saying that the engine is cranking, but won't fire, or absolutely nothing happens when you turn the key? Could just be a pulled fuse...

It does absolutely nothing.

yea, fuses or maybe a disconnected clutch switch if your car is a manual trans.... i too doubt its anything complicated to repair