This articles provides some details on why touch may not be working on some touch screen devices and how to fix this issue

Issues: Touch not working at all. Touch not working on parts of the screen. Dead touch band on screen. Lower portion of screen dead. Upper portion of screen dead. Right side of screen dead. Left side of screen dead. During alignment cannot touch one of the targets. 

IMPORTANT: On Elo touch monitors, you must have the touch cable connected. On newer models this will typically be a USB touch cable. Some older model monitors may have an RS232 DB-9 touch cable, or both USB and RS232. Do not mistake the VGA connection for a touch connection. VGA is only for video and has nothing to do with touch. If you have the touch cable connected and are still having the issues mentioned at the beginning of this article, continue with the below:

The common cause for touch issues is something sticking to the front of the touchscreen glass. If your Elo monitor shipped with a protective sheet or release liner on the front of the glass, you must remove it for touch to work correctly.

On zero-bezel monitors, many customers will place items on the edge of the screen in the black border area, ie: stickers, labels, sticky notes, asset tags, ID tags, tape, plastic cover sheets, etc. This will cause the touch to not work or only work on parts of the screen or sections of the screen. You cannot have anything sticking to the glass.

Often times customers will report this issue after upgrading their Operating System. The common cause is after they upgrade their system they place an ID sticker or Asset tag on the glass to indicate the system has been updated. This will cause touch issues. Anything applied to the glass must be removed to allow the touchscreen to perform correctly. More about this in our Knowledge Article HERE

   
If anything is sticking to the glass, you must remove it, clean the glass of any left-over sticky residue, cycle power to the unit by removing the power cord for 30-seconds and then reconnecting. Then test the monitor again for proper touch.