I have a few PCs in a warehouse that have a bar code scanner attached as a keyboard input device. The scanner is setup to automatically scan labels as they are printed on a label printer.  A PC window application then captures the inputs from the scanner as labels are printed.
This solution works fine until a 2nd window pops up for some reason, taking the input focus away the capture window.

Can I config Windows somehow to never leave a certain application, or never popup another window? 

( for example, I know I can shutdown explorer.exe with ctrl-shift  right click. How to do that from code? )