USB 16GB stick doesn't show up

I have a small 16GB stick that isn't showing up at all on desktop, profiler, or disk utility when I plug it in. I've tried it on a MacBook running Snow Leopard, and Powerbook, running Tiger.

It was originally formatted on a mac, and I used it a couple of times, and I've just reformatted it in a Yamaha Keyboard, in a format that I know can be read by macs (I've formatted another 8GB USB stick with the keyboard, that reads OK on my mac).

So basically, it's working on Windows, not on mac. Any advice or suggestions?

I've tried rebooting with it connected, still no joy.

I would say go ahead and reformat it again but this time use a PC. Erase it and then format it as FAT-32. Do not use Disk Utility from your Mac to do the formatting.

Also some memory sticks have a remarkable short lifespan no doubt due to the incredible amount of storage on such a small space.