Dell XPS/Dimension XPS Gen 4 - Manual (Page 31)

4. Press in on the tabs on each side of the drive and slide the drive up and out.
Installing a Hard Drive
1. Unpack the replacement hard drive, and prepare it for installation.
2. Check the documentation for the drive to verify that it is configured for your computer.
3. If your replacement hard drive does not have the bracket rails attached, remove the rails from the old drive by removing the two screws that secure
each rail to the drive. Attach the bracket rails to the new drive by aligning the screw holes on the drive with the screw holes on the bracket rails and
then inserting and tightening all four screws (two screws on each rail).
4. Install the hard drive into the computer by gently sliding the drive into place until the tabs securely click into position.
NOTE: If you are installing a hard drive in the lower bay, place the drive in the bay so that the power connector is on the left-hand side (opposite of the
top hard drive).