usb can open

Go to Applications->Accessories->Terminal

Without the device(s) plugged in, type:

lsusb

and note the output.

Plug one of the devices in - wait a few seconds for Ubuntu to react to it and, again, type:

lsusb

and let us know what changed.

By the way, what size memory do these devices have?

I have an older PC that won't take my camera's new 4GB microSD card. The PC sees that something is plugged in but I can't open it. I can open it on more modern PCs. I've seen this a few times at work - older PCs and laptops not being able to read larger SD cards or USB thumb drives.

If you have one, start with as small a memory as you can find (say, 256MB or 512MB - these are usually safe on any PC I've ever worked on). If it works for a small memory but not a large one, then it's the USB port's inability to read larger memories that is the problem and, to my knowledge, there's nothing you can do about it short of buying and additional, more modern, USB card.

If you can't even read 256MB or 512MB then we need the lsusb output I mentioned above.

this doesnt work at all all dont know what to do LEGOmaniac..isusb solution..
the problem is that i have a 4bg...

What is a 4bg?

yes its a 4gb flashdrive connected to my nikon d40 with a lot of photos

Try using a smaller Flash drive.