No signal on monitor and power in USB ports

Hey,

I seem to be not getting signal form my motherboard and I realised that my usb port wasnt getting any power (a brief light up on mouse/keyboard, and then nothing).

All the fans cept my back exhaust fan (connected to MOBO) are working, and so are the LED lights.

I've re assured that all the wiring is connected correctly, reseated every chip, reset CMOS, tried different PSU*** and GPU and boot with one stick of ram.

I get no Beeps and I never had any beeps from my computer before

*** when I changed the PSU from 300w to 400w I had an output on the monitor. Displaying my start-up page before bios, display some sort of texts and turn off again. When restarting it again I get absolutely nothing. Reseting the GPU again with the 400w plugged in I get the same screen and the computer powers off again.

I'm starting to think its my MOBO.

please help!

PS: Very old build