My unit does not seem to recognise my usb device and ideas

Control panel admistrive tools,computer management,device manager scroll down universal serial bus controllers you should see a yellow question mark?
right click to reinstall drivers or
if you can see your usb but its not working
ports(com&lpt)right click update driver or
scroll to disk drives if you can see your drive + to expand right click you should see options to update driver,disable,uninstall scan for hardware changes. or
select properties you should see options in the general tab to troubleshoot,policies,volumes,driver and details under the driver tab you will have the options to check the driver details,update driver,rollback driver or uninstall
hope this helps