Quite possible, Carl. The first thing to do would be to try another USB cable and see if that makes any difference (unlikely, but worth a shot). If still no go, then you need to transfer the drive itself into a new enclosure as the USB/SATA (or USB/IDE) interface in your existing enclosure has failed. I've had this happen to me, only my drive was being intermittently recognised and it didn't cause my other USB devices to stop working. Just make sure that you get an enclosure to suit the type of drive, SATA or IDE.