Originally Posted by Jarmusch

Almost all motherboards have a buzzer nowadays, you don't even need to plug in the case speaker, and very few cases come with a speaker anyways.

It should beep during boot, if it doesn't it's not a good sign, the cpu could be fucked. Try to plug speakers/headphones to the sound jacks on the board (try them all) and see if you hear an error message. I had an asus board some years ago that did that, a female voice repeated the error over and over.

Also try to look in the troubleshooting part of the motherboard manual, there's some hints there that can help you figure out what's wrong with it, like the small led on the mobo can red or green etc.