Answer:
The two most common types of external zip drives are USB (little square plug about he width of your thumb) and parallel (wider square plug, about three fingers wide)... I will do my best to explain how to install either
USB: Put in the CD & run the driver install utility BEFORE plugging the drive in. If you don't have the CD, you can download them at iomega's website... see link below.
Once the software is installed, simply plug the drive into any USB port on your computer. It should auto-detect, install & then show up as a drive letter under "my computer"
Note: If you are running XP or vista, you shouldn't have to download any drivers at all, they are supported natively by the OS
Parallel. Just the opposite. Plug the drive in first, and THEN install the drivers. Some new systems do not come with a parallel port, don't worry, you can get a parallel to USB converter for $20 to $40 at any nearby electronics store.
Additionally, if you have a parallel port, have done just as i said above & the drive is not detected, the parallel port on your system may be disabled. Consult your computer or motherboard manual on how to enter BIOS and enable it.
I should conclude by saying that there are firewire, SCSI, serial (and probably SATA) zip drives out there. They are not as common, but if you have one of these, you might start a new question & make a note of what type the drive is.