this step by step procedure
1. delete the version 1.89 c
2 download and install the official version 1.92 from the site which istallera' the correct version of c++ does not connect absolutely the kess
3 uninstall the their computers 1.92 from disistallazioni programs and go to c and delete the folder on their computers
4 restart
5 install the version 1.89 + driver
6 launch their computers
if you want to try..........