Dell Dimension 4600C - Manual (Page 29)

2. Press in on the tabs on each side of the drive, slide the drive toward the I/O panel, and then remove the drive from the computer.
Installing a Hard Drive
1. Unpack the replacement hard drive and prepare it for installation.
2. 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).
3. Install the hard drive into the computer by gently sliding the drive into place until you hear it securely click.
4. Connect the power and hard-drive cables to the drive.