DDD

Have you tried re-installing the driver that worked in compatibility mode?

To install in compatibility mode do the following:

Right click the installer>properties>compatibility>choose OS

http://windows.microsoft.com/en-US/windows-vista/Make-older-programs-run-in-this-version-of-Windows?SignedIn=1
(works in vista, win 7, win 8, and win 10)

Hello. I upgraded my software from windows 7 to windows 8.1. Before the upgrade there was no issues with the touchscreen. Its why I bought it in the first place. After the upgrade, the DRIVER for touchscreen says it is not valid and nothing Ive tried has repaired or updated the driver. Other forums have suggestions, but that hasn't helped. Thanks. My pc model is the HP Touchsmart 420-1000t.

Hi,

Drivers for HP Touchsmart 420-1000t can be found in

http://support.hp.com/us-en/product/HP-TouchSmart-400-Desktop-PC-series/5146292/model/5155758/drivers

it lists up to system Windows 8, but as I know, device for Windows 8 can mostly work fine in Windows 8.1 system, please manually download and install latest drivers there, test the issue again.

If still fails, you might contact the HP support to check if there're some compatibility issues.

http://support.hp.com/us-en/product/HP-TouchSmart-400-Desktop-PC-series/5146292/model/5155758/more-options

NOTE This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on these sites.