I have an old external hard drive (5yrs) that I used on a G4. I tried to plug it into my 10.5.8 and it will not register. I tried it on 3 different computers. I am tiring to use it for work (school teacher). I have an older Mac at work that it did show up on so I can get the info off. How do I get it to work on my newer one? I have no disk for it. I am also sending this problem to the company.