When I downloaded XCOM from the CA support site, I received an .iso file which is a CD image. However we don't have CD burners available at work. There are a number of free utilities available that "break apart" an .iso file, however on closer examination, they all appear to be free for private use only or free trial. I don't want to download a utility program from a company I never heard of either.
Winzip or other zip type utilities will "unzip" an .iso file. Some of these are free. Certain platforms, such as Linux PC allow you to mount an .iso file.