Dell Dimension 2100 System Reference Manual page 65

NOTICE: Be careful not to bend any of the pins when you unpack the
microprocessor. Bending the pins can permanently damage the
microprocessor.
3. Unpack the new microprocessor.
If any of the pins on the chip appear to be bent, obtain technical
assistance.
4. Align the pin-1 corner of the microprocessor chip with the pin-1 corner of
the microprocessor socket, as shown in the following figure.
NOTE: You must identify the pin-1 corner to correctly position the chip.
The pin-1 corner of the microprocessor is the beveled corner. The pin-1
corner of the socket, labeled "1," is the front-left corner of the socket as you
face the back of the computer.
5. Install the microprocessor chip in the socket (as shown in the preceding
figure).
NOTICE: You must position the microprocessor chip correctly in the
socket to avoid permanent damage to the chip and the computer when
you turn on the system.
a. If the release lever on the microprocessor socket is not all the way
out, move it to that position now.
b. With the pin-1 corners of the chip and socket aligned, align the
pins on the chip with the holes in the socket.
1 Pin-1 corners of
chip and socket
aligned