I had this application installed in my computer but when my computer crashed, the application disappeared and when I try to re-install/uninstall I encounter problems.
These applications have their own uninstaller you can use to remove them from your system. In case there is no such possibility, you can forge the uninstall process using an application that handles problems of this kind. 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.