This article outlines the reasons why touch functionality may not work on Windows Embedded Standard 7 (WES7) and potential solutions

Although the WES7 Operating Systems are no longer supported by Microsoft or Elo Touch Solutions, the following information may assist if you are still using one of these systems.

There are two versions of WES7: WES7E and WES7P
WES7E (Windows Embedded Standard 7 Embedded) does not include Windows Tablet Services by default. Windows Tablet Services are necessary for the full functionality of multi-touch monitors, which means that if you're using a multi-touch monitor with WES7E, you will need to manually install the appropriate drivers and services to enable touch functionality. This is one of the limitations of WES7E compared to WES7P, which may include more comprehensive support for such features.
 

Elo Multi-Touch monitors, including PCAP, IR, and IntelliTouch Plus, require Windows Tablet Services to operate. To enable a Multi-Touch monitor on WES7 systems lacking Tablet Services, you will need to install the Elo Multi-Touch driver using the Touch_MouseMode option, also referred to as "Forcemouse" in earlier drivers. Please note that this method will only support single touch functionality on the monitor.