external HD unreadable

I have a Fujistu P Series Lifebook, and am attempting to access my PC’s HD to correct partition issues. I am using an aluminum external case, Combo USB 2.0 to SATA & IDE hard disk. I have connected 3 different Maxtor PC HD’s, I was able to mount an image to one of them. The other two appear in the “Safely Remove Hardware” utility, but do not appear in My Computer. Please advise. Thanks!