Start by checking if you can see the options Pen and Touch, and Tablet PC Settings in Settings, then you know that the PC is reading the connection from the touchscreen. If you only see Devices and Printers, AutoPlay, Sound, & Power Options, then the touchscreen monitor is most likely not connected correctly. 

Fix Touchscreen Not Responding

1. Check Physical Connections
   • Make sure the USB cable from the touchscreen is securely connected to the PC.
   • If using an adapter or hub, try connecting the cable directly to the PC.
   • Unplug and replug the USB cable, then wait a few seconds.
2. Test with a Mouse
   • Connect a regular mouse to the PC.
   • If the mouse works but the touchscreen doesn’t, the issue is likely with the touchscreen hardware or drivers.
3. Check Device Manager
   • Press "Windows + X" > choose "Device Manager".
   • Expand "Human Interface Devices".
   • Look for a device labeled "HID-compliant touch screen".
     • If it’s listed, right-click and choose "Enable" (if disabled).
     • If it’s missing, continue to the next step.
4. Recalibrate the Touchscreen
   • Press "Windows + R," type "control" and press Enter to open "Control Panel".
   • Go to "Hardware and Sound" > "Tablet PC Settings".
   • Under the Display tab, click "Calibrate".
   • Follow the on-screen instructions to recalibrate the touchscreen.
5. Restart and Reconnect