Compaq 239158-999 - Mini Tower - Power Supply 250 Watt Hardware Reference Manual page 27

Hardware Reference Guide
Open both latches of the memory module socket 1, and insert
4.
the memory module into the socket
Installing a DIMM
5. Begin by installing a module into the socket nearest the
preinstalled module, and install the modules following the
numerical order of the sockets.
6. A memory module can be installed in only one way. Match the
notch on the module with the tab on the memory socket. Push
the module down into the socket, ensuring that the module is
fully inserted and properly seated
7. Repeat steps 4 to 6 for any additional modules that you want to
install.
8. Replace the access panel.
9. If you normally lock the Smart Cover Lock, use Computer Setup
to relock the lock and enable the Smart Cover Sensor.
The computer should automatically recognize the additional memory
the next time you turn on the computer.
Hardware Upgrades
2
.
3
.
2-9