Are you saying that touch functioned in Windows 8? It should not have worked in Windows 8 unless you were using the Windows 7 Touch driver?
* The ST2220T officially does not have touch functionality on Windows XP/8/8.1
* The User's Guide touch screen specifications states: Win7 multi-touch and Windows 7 compliant
* The User's Guide touch screen operating system compatibility states: Single Touch = Windows Vista, Windows 7 Starter, Home Basic, Home Premium, Ultimate, Professional, Enterprise Multi-Touch (two points) = Windows 7 Home Premium, Ultimate, Professional, Enterprise