I dont know much about these LCDs but if they are anything like regular LCDs you might try uninstalling all drivers for it.
Connect another monitor to it. Now install the drivers for the montior but not touchscreen. Turn off pc connect the VGA cable to DWW-700H and the PC. Boot back up. Connect the USB..windows will prompt to install drivers automatically dont choose that option, choose to install from disk. Tell me how it works..
sometimes USB drivers mess up if you install the improperly, id you did do that before hand..then i dont know what the problem can be.