Touch screen is not responding with the stylus

Have you already performed a clean reset? You might know that it will restore your device to its factory settings, thus deleting everything you have installed, as well as your personal data and settings. So, it is strongly recommended to backup your data beforehand.
Anyway, to perform a clean reset, press and hold the Calendar, Power, and Messaging buttons, and, whilst keeping them pressed, press and hold the reset pin with the stylus pen. When your device restarts, release the buttons and the stylus pen from the reset pin.
Hope it works for you.
Cheers! Carlos

the touch screen plug on the motherboard is disconnected

This is a known issue with this device. You can call the manufacturer and try to get them to send you a new one, or go to the attached link. They sell parts very reasonably and the installation is a breeze.

http://www.pdasmart.com/

I encountered this problem today, and I have figured out a solution!

Switch the Wireless switch on the bottom of the Pocket PC to the Off position, then back on.

Voila, your touch screen should respond now.

do a hard reset, i.e., hold the power button while resetting the phone using your stylus oen.

SOLUTION:

KEEP PRESING CALENDAR+MAIL+POWER BUTTON
AND INSERT STYLUS IN RESET BUTTON

Solved same problem.
Same model ipaq 1940.
Sorry for my bad english;this is what You can do:
Open the ipaq
Remove the mainboard
My problem was the connection between LCD and Touchscreen.
So I solved putting on the connection 3cm of tape to have a fully working contact.Indeed, the lower part of cable, with the 2 little holes was disconnected.
After this all becames to life!
I hope helps!
Vit :-)
In italiano: 3 cm di nastro adesivo fra LCD e touchscreen.Il loro contatto non era perfetto.Ora tutto funziona.Con un po' di manualità si riesce a fare senza problemi!
Saluti, Vit

A Reset of your Pocket PC is equivalent to "Restart" of a desktop computer. Carry out the Reset only in such unusual cases as when a button or tapping the screen does not respond. When your Pocket PC is reset, no data will be deleted. All stored information like Addresses, Contacts, Tasks or Programs are still stored in the Pocket PC memory. To Reset the Pocket PC, the power must be on. Then press the Reset switch with the stylus, then release. Your Pocket PC should function properly thereafter. If the functions cannot be restored, even after the reset button is pressed, Initialise your Pocket PC (refer to the FAQ article: How can I initialise my Pocket PC (Factory Reset). If you have further questions, please refer to the Instruction Manual page 12-4 (172 of 182).

A Reset of your Pocket PC is equivalent to "Restart" of a desktop computer. Carry out the Reset only in such unusual cases as when a button or tapping the screen does not respond. When your Pocket PC is reset, no data will be deleted. All stored information like Addresses, Contacts, Tasks or Programs are still stored in the Pocket PC memory. To Reset the Pocket PC, the power must be on. Then press the Reset switch with the stylus, then release. Your Pocket PC should function properly thereafter. If the functions cannot be restored, even after the reset button is pressed, Initialise your Pocket PC (refer to the FAQ article: How can I initialise my Pocket PC (Factory Reset).

A Reset of your Pocket PC is equivalent to "Restart" of a desktop computer. Carry out the Reset only in such unusual cases as when a button or tapping the screen does not respond. When your Pocket PC is reset, no data will be deleted. All stored information like Addresses, Contacts, Tasks or Programs are still stored in the Pocket PC memory. To Reset the Pocket PC, the power must be on. Then press the Reset switch with the stylus, then release. Your Pocket PC should function properly thereafter. If the functions cannot be restored, even after the reset button is pressed, Initialise your Pocket PC (refer to the FAQ article: How can I initialise my Pocket PC (Factory Reset).