Dell PowerEdge C2100 Hardware Owner's Manual page 78

NOTE:
install the memory module in the socket in only one way.
4 Press down on the memory module with your thumbs until the ejectors
lock into position. See Figure 3-11.
When the memory module is properly seated in the socket, the ejectors on
the memory module socket align with the ejectors on the other sockets
that have memory modules installed.
5 Replace the cooling shroud. See "Installing the Cooling Shroud" on
page 61.
6 Close the system. See "Closing the System" on page 59.
7 Reconnect your system and peripherals to their electrical outlets,
and turn on the system.
8 Start up the system, press <F2> to enter the System Setup program,
and check the System Memory settings on the main System Setup screen.
The system should have already changed the value to reflect the newly
installed memory.
9 If the value is incorrect, one or more of the memory modules may not be
installed properly. Repeat step 3 through step 8 of this procedure, checking
to ensure that the memory modules are firmly seated in their sockets.
74
Installing System Components
The memory module socket has an alignment key that allows you to