Can a touch screen be disabled on a computer?

The quickest way to disable a touch screen would be to just not use it. If your computer offers both keyboard and mouse and touch screen controls, don’t touch the screen. I have a touch screen on my Windows 7 computer, that I seldom use, though I use the touch screen on my Windows 8.1 tablet all the time.
Here’s what you can try on Windows 8.1. Find device manager on your computer by typing in  your  Search Charm and clicking on the result.

Choose Human interface devices.

Under HID compliant devices, look for a listing for HID compliant touch screen.

You can right click on that and choose disable.

For a Windows 7 computer type Pen and Touch input into the search box in your Start menu and click on the result.

Select the Touch tab and uncheck the box next to Use finger as an input device.

Of course, don’t do this on a tablet. You probably won’t have the option, but don’t. Your detachable keyboard could fail and then you wouldn’t be able to control the device.
Hope this helps.