Acer z3101 vga problem

I am trying to connect my xbox 360 using Xbox 360 VGA HD AV Cable to my Acer Aspire Z3101 22 Inch All in One Desktop PC to use the monitor for my xbox.
I have the vga cable going from my xbox in to the D-Sub VGA port on my pc but am getting no picture. Do I need to some how put my pc in to vga mode? I have tried pressing f8 on bootup but there is no option to enable vga mode, there is just some options for safe mode. Can some one please tell me what the problem could be.

Thanks in advance for any help.

 

Having looked at the specs I suspect that you probably have it connected to a VGA out port. On the spec It doesnt specify whether it is VGA in or out but unless there is a button on the actual box to toggle the display source I would guess that it is a VGA out for running dual screen.

Ergo it is not possible to use this as a display for your xBox

Sorry