external flash drive not recognized by lion

I bought a new mac mini with OS Lion and now I discover that external drives are not recognized. Can I resolve this?

Perhaps the drives are being recognized but are simply not appearing on the desktop. Check this by opening the Finder's preferences. Go to the General tab and make sure External disks is checked.

Thanks for the reply .. I had already tried what you suggested. However, I tried two other flash drives and they work .. after all my fadoodling around I nearly fell off my chair. The one I was writing about still doesn't appear .. I was wondering if it could be formatted somehow .. but how, if it doesn't show anywhere? B

Have you tried launching Disk Utility to see if it appears in the list of drives in the left pane? Sometimes if a drive's directory structure is damaged Disk Utility will "see" it where Finder cannot. If that works you should be able to see and format it. DU may also be able to mount the drive without needing to reformat it.