How to Install an Internal Modem on system Installing an internal modem is not an easy task. You have to open the computer to install modem cards. Given steps applies to all computer system. Shut down the computer and disconnect all peripheral devices from the computer, then remove the computer's cover. Find a slot that matches the pins. PCI modems have fewer pins and fit into a smaller slot than ISA modems. Put new modem into that slot if it will physically fit. First unscrew the metal plate on the slot holder on the back panel, and insert the modem...