Battery is the most likely. Get someone with a multimeter to check it. If it's under 12v then it's dead. If the lights have been left on accidentally, it may be able to be recharged, otherwise it's new battery time.

If the battery is OK, then you have to start tracing the leads / fuses / etc to find the actual problem,

But 95% chance it's just the battery.

HI, yes battery

the battery would be a good place to start at ! it also could be dirty battery cable ends or the battery posts are corroded !

It could be the battery or the main fuse or a battery cable or a defective ignition switch, ad infinitum.

Battery is dead. Go get a New One required. Batteries do not last forever, lol.

I have a 2008 honda civic LX. When I put the key in the ignition nothing happens, no light, nothing. Also, the remote lock/unlock doesn't work. Neither does the locks inside the car? Is it the battery?