You may have on-board graphics card... but that is not
configured... that is why no beeps...
Or when some dumbo build that PC, they didn't plug in the wires for
the error beeps. If you still have your motherboard manual, you can
check the LED lights errors. This will need you to open up the CPU
casing and look inside. The LED lights on the motherboard does
indicate some form of failure if there's no beep errors
produced.