Dell Dimension 2100 System Reference Manual page 51

2. Lay the computer on its side.
3. Press the release latch while lifting the power supply.
4. Rotate the power supply out of the computer while keeping the drive
power cables clear.
5. When you rotate the power supply back into the computer, gently lift the
and hold the drive cables out of the way.
6. Rotate the power supply into position until its release latch clicks. Lay
the drive power cables along the top of the latch.
Front Panel
Drive power
1
cables
2 Power supply