Why is my BMW X3 not starting?

I recently bought a used BMW X3 and it's been running great. However, yesterday when I tried to start it, nothing happened. The lights and radio turn on, but the engine won't start. What could be the problem and how can I fix it?

First of all, make sure your battery is fully charged. If it's not, jump start your car or get a new battery. If that's not the issue, it could be a problem with your starter motor or ignition switch. It's best to take it to a mechanic to get it checked out.