Micro sd chip

If you mean you don't know what the drive letter is then one way you might be able to easily determine that is by using the "Safely Remove Hardware" icon that you should have somewhere in your system tray area by the clock.

Another way is to use your directory tree (Windows Explorer) and generally it's easy to rule out which drives are fixed hard drives so any listing that remain as uncertain can simply be clicked on to view and you'll get a no disk error if there's nothing attached to that slot in the memory card reader.

I hope that's what you were asking.