Trying to play from an external drive created unexpected results

I have a Firelight drive that was full of music from another computer so I plugged it into my iMac then held down the option key while opening itunes.\
Choose Library didn't work so I clicked on Create a new Library in itunes.
I wanted to just play and burn the songs from the drive but they instead were imported to iTunes.
This was okay though, I saved the songs to dvd and deleted them.

What is troubling is this;
When I click on my hard drive on the desktop it lists all the music that was imported so I guess I really didn't delete anything when I deleted everything in iTunes.
Question 1 ) why did this happen.
I suppose I can go ahead and delete everything but....
Question 2) all that will be left on my iMac's drive after deleting the music is a Users file and a file with a curved arrow on the bottom left corner that says "Users Guide and Information"
I am sure that there were a lot more things listed on the iMac drive before.
Everything seems to be working fine and the Home,Applications,Documents,Music and Pictures icons are all unchanged.

One more thing.
The Firelight would not turn off or go to sleep even when I turned off the computer. Before it always went to sleep when the computer went to sleep.