I bought a 10.1 inch acer emachines net book and I am trying to run it through a plug and play acer monitor but when I go into settings and try to check the 'Use this device as the primary monitor' box I lose the big monitor altogether.

On a mates monitor everything works ok and I could shut the net book and continue working on the other screen.

He installed a driver for the plug and play but I still can't set it as the main monitor, it acts as an extension of the net book monitor and I have to drag whatever is open onto the P&P and work there. No big deal but I was wondering if there was some way around it.

Maybe try Lower the Screen Resolution and then try again. You need to get both screen working first so start by making it a second image of the notebook screen once you have an image on both them try making it the primary monitor. i can take a bit of fiddling to get it working i know have spend along time getting Large screen TV working for media centre etc.