My new ASUS X202E Touchscreen stopped working shortly after buying it last month. Maybe it was the Windows 8.1 Update? I dunno. I couldn't figure out. Spent 4 hours reinstalling factory drivers & pulling out my hair upon finding the solution.
SOLUTION that WORKED for ME:
Goto Windows Device Manager (WDM) @ section, "Human Interface Devices" (HID).
Note, you will NOT see anything labeled, "Touchscreen" in the entire HID list.
Right-Click menu for each HID should look like the following list:
"Update Driver Software..."
"Disable"
"Uninstall"
"--------------"
"Scan for hardware changes"
"--------------"
"Properties"
Obviously, if the right-click menu's 2nd item = "Disable" then it's already
Enabled
SOLUTION is to ENABLE each HID that 2nd item = "Enable"
ALL OF THIS WOULD'VE BEEN MUCH EASIER IF THE DISABLED HID WAS LABELED, "TOUCHSCREEN"
but sad to say it wasn't... and that's why I had to check each HID if it was enabled or not.
Several Lenovo laptop users experiencing similar Touchscreen problems blogged about finding this solution & all mentioned their BIG disconnect was NOT being able to see anything labeled, "Touchscreen" in the entire WDM.
Hopefully, your situation is easier just by downloading an OEM fix but that wasn't my experience.
Now, if Microsoft will only allow me to download an image of the Windows 8.1 Pro that I purchased thru their online store 2 weeks ago, I should be on my way...