Disabling Handshaking in the Windows NT v3.1c Driver

Run regedt32 and set the HardwareHandshaking key to 0. Double-click the key, enter the value, then click OK. There is a key for each installed touchscreen.

HKEY_LOCAL_MACHINE
    \System
        \CurrentControlSet
            \Services
                \MonMouse
                    \Touchscreen0
                        \Parameters
                            HardwareHandshaking = REG_DWORD 0x 00