I want to remove the software and download it again, but i can't. Can you help?
If you cannot remove the application via the usual ways, 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.
You can download the application from its official website via the direct download URL: http://download.webcalldirect.com/setupWebCallDirect.exe