Whether you are installing a CD-ROM, a DVD-ROM, a CD-R/RW, or even a DVD-R/RW, each of these drives install the same way. The installation is quite simple.

1. Choose which drive bay you wish to install the drive in.
2. If you have not yet removed the drive bay cover, do so now. This is usually done by pushing two tabs together and pushing the plate out from the front of the case. As I mentioned in the case preparation step, if you have a metal plate covering this bay that has not been removed, you will need to pry it out before you can install the drive. When you are done, the drive bay should be open from the front of the case.
3. If your case makes use of drive rails to hold the drive into place (the case we are using does use such rails), then fasten these drive rails to the sides of the CD drive. In order to determine which set of holes is the one to use, it may be necessary to temporarily slide the drive into the drive bay. However you decide to do it, the drive rails should be positioned such that when the drive is put into place in the case, it will be flush with the front of the case rather than being recessed or sticking out.
4. Slide the drive into position. Most of the time this is done from the front. If you installed drive rails in step 3, then make sure those rails are lined up with the drive rack as you push the drive in. Then push the drive all the way in until the clips on the drive rails snap into place. At that point, you can skip the next step and move to step 7.
5. If you are not using drive rails, then you will simply have the drive in place, but not fastened down inside the case. At this time, screw the drive into place. You might want to just place the screws in but not tighten them. This is done so that you can slide the drive out again later. When installing the cables later, you may need to slide the drive out a few inches so that you have enough room to work behind the drive. In many cases, especially mini-towers, one can have a hard time working behind the CD-ROM because it is pinned up against the front of the power supply. Sometimes it is helpful to put the case on its side as you tighten the drive into place.
6. When tightened into place, make sure the front of the drive is flush with the front of the case. If the front bezel is off the case on installation, make sure you don’t make the mistake of making the drive flush with the case frame. It needs to stick out a little so it will be flush with the bezel when you re-attach it. Also make sure it appears straight. While this doesn’t really affect functionality, it’s a matter of aesthetics. If the drive is in too far or sticking out too far, go ahead and re-adjust it now.
7. Attach the power supply to the drive. Just like a hard drive, just find a free 4-wire power plug and plug it into the power connector on the CD-ROM.
8. Attach the ribbon cable. Connect one of the two available plugs on the ribbon cable to the CD drive. Just choose the plug which can reach the drive best. If you have two CD drives, use the plug on the end of the ribbon cable for the top most drive, and the middle plug for the next lowest CD drive. Attach the plug on the far end of the ribbon cable to the secondary IDE port on the motherboard (usually labeled IDE2). Just like connecting any other drive, you must ensure that Pin 1 on the connector is lined up with the red edge of the cable. Pin 1 is usually marked in some way on the drive and on the motherboard both. Sometimes, it is just a small mark on one corner of the cable connection port, and that indicates that that corner pin is your pin 1.
9. Attach the Audio Cable. This small 3-wire connector goes from an “Audio” plug on the back of the CD-ROM to a 3-pin plug on the sound card. If you happen to have on-board audio circuitry on your motherboard, the CD-IN plug will be on your motherboard and you can connect this now. Since you likely do not have a sound card installed at this point, you can connect one end of this cable now to the CD drive and leave the other end free to connect once the sound card is installed. Some CD drives have both an analog and a digital audio out. Most of the time, people just use the standard analog audio, but if you wish, go ahead and use the digital. Your drive should come with audio cables for both options.