Legally, no. The DMCA and similar laws in other countries do not grant you the right to download a copy from the internet, even if you own the original. You must create your own backup.
Dicho esto, aquí te presentamos los pasos para descargar Call of Duty: Modern Warfare 3 para Wii en CoolROM: descargar call of duty modern warfare 3 para wii en coolrom