Usb Ejection

So I'm trying to make a very basic usb hub ish thing the projects not to important but there is two key things i need to do with an Arduino.

  1. The #1 thing I need to do is have it eject a USB stick, I will know the device letter but that's about it (I can give it more info if needed though) and I haven't the foggiest idea on how to do that

  2. less important but still would love to know is how detect if a usb of a certain drive letter is plugged in

(mind you this is getting info about the PC its plugged into)

Edit: To clarify when I say eject i mean the safety eject system that windows has

I would assume you close all open files, then power it down. It will not eject unless there is something mechanical to do that. From my memory many years ago the drives were enumerated starting with A: and B: for floppies, C: for the first hard drive, D: the second etc. File type devices such as USB sticks, DVD, CD, etc were also enumerated. No guarantee how it will come out.