As far as I know, Touch Screen just a very thin layer of resistive sensitive meterial that stick ontop of your monitor.

Beside this, there also have four (most of the touch screen output) TTL (Transistor Transistor Logic) anolog signal output pin that represent your current X1, Y1, X2 and Y2 location on the screen. (I think it is in AC Alternative Current format)

Normally, the tourch screen come with the serial port interface (RS232C standard ). Whereby, you can capture all this signal through the HyperTerminal application. But you may need to convert all the received signal into digital form and that where the Driver come from.

You can write your own drive with the Win9x, WinNT or WinCE SDK or DDk toolkit to help you to archive it.