Verify that the front of the drive lines up correctly. Others require you to screw the drive into the bay anyway, using holes in the front of the drive bay. Either way, make sure the drive is not free to move around when you are done. If your case has one of these, detach it from the case. Then screw the drive into the plate, and reinsert the plate into the case.
Some plates detach from the case using a single screw.
Some cases, especially desktops, use a removable metal box into which the drive is mounted. The procedure here is similar to that for direct mount, above, except that you have to remove the box first and insert the drive into it, then remount the box. Be sure to check the alignment before you tighten the screws. Ensure that it is not loose in the case. This page has been served 29332 times.