For manually uninstalling the software please follow the instructions.
To uninstall the software you may need to terminate the application when it is in scheduling mode. Terminate the File Shredder program going in to the task manager(CTL+ALT+DEL) or from the system tray you could find file shredder running, right click on the icon and select exit option.
Once you have terminated the software you could uninstall the software from add or remove programs from the control panel.
Also, the software when installed adds a shared dll which provides context menu integration. At the time of uninstall the system must be restarted in order to remove this shared dll file.