That said, move on: 

1.) Slide the hard drive into an available drive rail of the case. All cases have a space (maybe two) for a hard drive that is below the floppy drive bay and has no access to the front of the case. This is fine, since who needs to see their hard drive from the front? If the drive is smaller than the drive bay (if you are installing a 3.5" drive into a 5.25" drive bay), you may need to add rails or a mounting bracket to make it fit. Screw the drive into place, making sure not to force anything. And, uuhh, power connectors face the back. Good! 

2.) Attach the cables to the hard drive. Just like a floppy drive, connect the ribbon cable and the power cable. The ribbon cable goes from the primary IDE controller of the motherboard to the drive. Make sure the red edge of the ribbon cable is in line with Pin 1 on the drive. If you can't see Pin 1 marked, then it is the pin closest to the power connector. If you place the cable on backwards, you may get strange errors that make your new drive sound like it has died already. If you are adding a second drive, simply choose a connector on the same ribbon cable that is not used. Most ribbon cables come with two connectors: one on the end and one mid-way. In this case, it doesn't matter which plug goes in what drive. The computer looks at the master/slave jumpers to see which one is C. Also, ATA/66 drives must have an 80-wire cable instead of the older 40-wire's. 

3.) To double-check, you should have an installed hard drive, securely fastened. The power lead is connected and the IDE ribbon cable leads from the IDE 1 connector on the motherboard to the IDE connection on the hard drive itself. 

SCSI Drives 

If you are opting for a SCSI drive setup, then there are a few variations. First, you need to install a SCSI controller into one of your expansion slots. Then proceed: 

1.) You need to set any switches or jumpers that need setting on the new drive. In SCSI setups, each device gets its own SCSI ID, numbered 1-7. #7 is usually given to the adapter card. You may pick, then, any other unused address. You may need to take into account any little quirks in your adapter, such as special likings to other addresses that could cause problems a little later. You'll need the manual for this one. 

2.) Check for the correct termination. In SCSI setups, the adapter can hold up to seven SCSI devices. These devices are hooked up in a chain, usually with the adapter at one end and another device at the other end. This ending device must be set to be the terminating device, therefore ending the SCSI chain. In some cases, the adapter is in the middle of the chain, therefore you must terminate at both ends of the chain. You may need to consult the manual for any special termination techniques particular to your brand of drive. In general, a certain jumper setting will enable internal termination on the drive itself, eliminating the need for a special terminating plug. 

3.) Slide the drive in and connect the cables. Make sure that pin #1 on the ribbon matches up with pin #1 on the drive. 

When performing this physical installation, you'll find that it differs from case to case. With some cases, the drive rack is simply part of the case. With this setup, you simply push the drive into the case and screw it in. In other cases, the drive rack may be removable. Some have many separate racks, and some have one removable rack that can hold many drives. With this setup, remove the drive rack. This is usually done by squeezing two metal tabs together to release it. Then slide the rack out. Screw the drive into the rack. Then, slide the rack back into place where it was. 

When you are done, you should have a hard drive properly screwed into the case.