OK, I've got that circuit setup and the lights are turning off fine if I ground the gate pin of the IRF540, but the 2N2222 doesn't appear to be working, when I give the base of the 2N2222A 5V, the lights do not turn off, they remain on.
Perhaps you should post EXACTLY how this is wired up. The IRF540 is an N-ch mosfet. You do not ground the gate to turn them on. A ground on the gate is to turn it OFF
reread the post: ''the lights are turning off fine if I ground the gate''But yes I'm worried the NPN's base was shorted to 5V rail and destroyed.