@Gladiator54 There are some case raspberry fail to boot in my experience.

insufficient power from USB Adapter -> Try y to use 2/3 Amps Adapter

Broken Micro SD Card / OS FIle -> Try another uSD card

Polymeric Fuse failure -> It's self-resetting and usually return to normal operating parameters within a finite time, in such case check any shortage in the board PCB like small wires/coppers ..etc.

You can try load a new Raspbian OS with GUI and connect HDMI Monitor, if any error occurs you can see that, keep an eye on the ACT led (Green).