My computer is wierd, sometimes the onbard LAN doesnt work.
Sometimes the screen isnt picked up on start up, and will only be picked up by restarting.
Sometimes it freezes during boot (XP and ubuntu)
The system is brand new.
Does this sound like a motherboard issue? I dont know what broken motherboards do
Can I test it?
I have the same issue with a wireless keyboard. Try swapping any usb hardware on the back of your board. Sometimes windows fails to load a device driver. When windows fails to load the driver for my keyboard, I have to change my wireless usb stick to a different usb port get a it working.