boot – PC does not post, random beep codes

I have a basic PC that does not boot. The fans come on, the led light comes on, there is no signal on the monitor, no usb lights, a light comes on a PS/2 mouse.

I put a speaker on the motherboard to get a beep code and each time I turn the computer on I get a different code (AMI). 3 beeps, six beeps, 9 beeps and even 12 beeps. I’m confused why I get several different beep codes.

I’ve tried using a different PSU.

The PC would sometimes freeze or restart randomly.

Thanks for reading!