The file is almost certainly a virus, and even if it isn't, your computer cannot run it properly.
Adobe Serif MM: Can You Download It for Free? (The Truth About This Multi-Master Font) Adobe Serif Mm Font Free Download
Here is everything you need to know about downloading it, why it is so hard to find, and what you should use instead. Do not let the "MM" confuse you. MM stands for "Multiple Master." The file is almost certainly a virus, and