Dell Inspiron 1100 - Manual (Page 103)

Adding and Replacing Parts 103
Modem
If you ordered the optional modem at the same time that you ordered your
computer, Dell installed the modem for you.
1 Complete the instructions in "Before You Add or Replace Parts" on
page 100.
2 Turn the computer over, loosen the captive screw in the modem cover,
and lift the cover away from the computer.
3 When you replace the modem, remove the existing modem:
a Remove the screws securing the modem to the system board, and
set them aside.
b Pull straight up on the attached pull-tab to lift the modem out of
its connector on the system board and disconnect the modem
cable.
captive screw
modem card
cover