I have owned my X-431 for several years now and have never had a problem with it.
Suddenly, when I power-up my X-431 I get the initial screen just fine (and it looks like always), but when I attempt to use the touch-screen to do anything at all with the stylus, nothing happens. It just stays locked on the initial screen view.
It's like a computer when the screen freezes completely, and everything, including he mouse, won't move.
Is there a Master Reset button or some way to "re-boot" the whole device, or re-install all default settings? Or is this an electronic or screen problem that would require intervention by a technician?
Most devices somewhere have a little hole though which a paper-clip can be used to access a ting reset button, and sometimes these are hidden under stickers or trim so that they won't accidentally activated, or fill with dirt or grease.
I also have a newer 431 with computer/Internet interface, but my older unit allows me to do many things with Pre-OBD II vehicles I still need to accomplish.
All Launch diagnostics are called X431. It sounds like you need to re-calibrate your screen. You don't say which model you've got but try this. For a Launch Master. Hold the power button down until the machine turns off and then touch the hot key several times immediately after you have turned the machine on again. You should then be able to re-calibrate the screen.
For a Diagun, there is a small hole on the back to reset the device and then calibrate the screen.
For a GDS, and the other Launches with a hard drive. If the machine is already on and the touch screen is not responding. Hold the power button down until the machine turns off. Turn the machine back on and then keep pressing and releasing the power button before the main screen loads up and it should load the calibration screen first. You can then re-calibrate the screen