Q: iomega usb zip drive not mounting to desk top

i have a external usb iomega 250 zip drive and i can seem to get it to mount to the desk top
i look on iomega website and it says that OS X dose not need any software install or additional drivers to work
i cant seem to get it to mount on the desk top
i have also installed the software from the disk and it wont mount
i them uninstall the software and try it again and still the same problem
as i know that this is a old beast of a drive system i am trying to get some songs off this disk from a 4 track zip disc recorder
any help would be great
thanks santini