Hi DNJ
Is the USB drive recognised as connected but you can’t see it in My Computer, or is it not recognised by Windows at all.
If the second then try changing the lead, and using other USB ports, if this still fails then there is probably a fault with the USB interface in the drive.
If it is the first one, then you have probably deleted the Partition and will need to go into Disk manager to create a new one. (Control Panel, Administrative tools, Computer Management then Disk Management)
BE CAREFUL WHAT YOU DO IN HERE and only highlight the drive that is shown as not partitioned, you can then right click and choose create.
Hope this helps

Bill