Something is closing a program, what could it be?

I have MasterCam 9 and Mastercam X4 installed, and they both worked perfectly. But a colleague borrowed my computer and tried to do something to the license because he was having troubles to do something with MasterCam X4. At the end he couldn't do what he wanted but now Mastercam 9 doesn't work anymore. It opens for a second and then it closes. I already uninstalled MasterCam X4 and 9 and reinstalled MasterCam 9, and deactivated the antivirus and the firewall and it still closes as soon as it starts to open. I installed it in a flash drive and it executes in another computer, but not in mine. What could it be? How could I solve it?