Desktop Lock will lock your desktop, but after you've finished the installation, it should provide the means to set up a password to avoid these situations. Lock your desktop, then press SHIFT, and click the turn off button. Choose restart, and the PC will restart in the Safe mode where apps are disabled from starting. Uninstall the application, reboot again, and reinstall the software one more time, but make sure to set up a password this time to avoid that situation.
