Other thread was closed. Hence new one.
I've tried a number of things now and had no success. I connected the USB stick to the back of the mac (in a USB port directly) and THEN booted the computer. I could see it in the Apple System Profiler but nowhere else. I tried booting first. Ditto. Tried same thing in all USB ports (powered hub, keyboard, comuter itself). Same each time. In fact, it shows up in the Apple System Profiler no matter which USB port I connect it to - the computer direct, the keyboard or my powered hub.
The option to turn the display of volumes on the desktop is turned ON.
The drive itself is switched ON.
The drive can't have expired, it's brand new.
If I open Disk Utility I see absolutely nada. No hard drives, no usb drives. Zilch. It just says "Select a disk or volume" but there is nothing in the list, not even my hard drives.
When I pull the USB stick OUT again I always get this message: "You have attached a drive that is not compatible with OSX. To continue with drive inserted click ignore".
Incidentally, I can access the drive under windoze and I can save things on it and delete them. I can also reformat it. The choices are FAT, NTFS or FAT32. Would reformatting ithe drive on a windoze machine help matters?
I am, as always, grateful for any help on this issue.