Computer turns on but monitor goes standby.

Hello,

When I turn on my PC the monitor stays in standby mode. The PC powers up but the monitor stays off. The light on the monitor stays orange, if I turn off the monitor and turn it back on the light goes green but then goes orange straight away.

i cant get to anything on my computer because the screen stays in standby mode. there are no noises when my computer is on from the speakers. there are also no beeps or anything but all fans are working motherboard led is on.

Its not the monitor because I checked it out on my other computer. everything looks like its plugged in well. I already change my power supply but still nothing happen. please do help me guys.

motherboard: asus p4ge mx

thanks in advance for your answers guys.