Modems only show up in a computer if they are installed as hardware in the computer itself...which can only be a Dial Up modem. Cable and DSL modems do not show up in the computer.

Phone (dial up ) modems use a phone line connector to hook up to the phone system in your house or apartment. Look for that on the back of the computer or sometimes on the side for a laptop!

Cable modems use a LAN connector that looks just like a phone jack but larger in size. Sometimes they can be connected through a USB port.