Touch Screen
HP LD4200 42" widescreen display
General Setup
Make sure the power cord is plugged in and the USB cable is connected to the computer.
Tip: Press windows key+p to extend screens. If the monitor is not registering touches, try turning flicks off (if it's on).
Troubleshooting
If touch isn't working at all:
1) Always make sure the USB is connected properly
2) Turn flicks off and see if that helps.
If touch isn't registering to the correct screen:
Go to control panel > tablet PC settings
And click on Setup next to Configure your pen and touch displays. Then select "touch input" - you may have to hit Enter to get the text to display to the correct screen, then touch that screen to configure it as the touch input screen.