TeraCopy is just an application like any other. This means you need to uninstall it through Control Panel > Programs and Features > Uninstall a program. But you can use another 3rd party application to force is uninstallation.
Try using Revo Uninstaller. Even if it can't uninstall the application normally, it will force it to uninstall by wiping out all traces of its presence from the system.
In the Revo Uninstaller interface, choose Quick Uninstall then follow the instructions and that's it.
