Dell OptiPlex G1 - Manual (Page 69)

When you reinstall the hard-disk drive bracket, place the lower-back tab of the hard-disk drive bracket into position (be sure that the opening in the lower-back tab is
over the alignment tab on the chassis); then rotate the front of the bracket down into position.
Hard-Disk Drive Assembly Removal
To remove the hard-disk drive, follow these steps:
1. Remove the hard-disk drive bracket.
2. Remove the four screws that attach the hard-disk drive to the hard-disk drive bracket.
One hard-disk drive attaches to the hard-disk drive bracket at the sides of the drive. The other hard-disk drive attaches to the hard-disk drive bracket at the bottom of the hard-disk
drive.
3. Slide the drive out of the hard-disk drive bracket.