ITUNES problem.

I am new to itunes and used windows media player for years. I just don?t like the fact that apple cripples you into their proprietary formats and I don?t appreciate that business model. But now I realize that I can use the itunes 8.2 with all of my mp3?s and other formats that are NOT aac files! At least I think I can..??

But the problem is that all of my 100gigs of a collection are gotten from many sources. Amazon unprotected non drm mp3?s and burned from a physical disc in different formats, either lossless or mp3 or wav? but none or very few are in aac format.

How can I transfer large quantity or songs and albums via my music folder and or windows media player to itunes and NOT delete the albums or songs from the windows player, JUST make a carbon copy of them in my itunes 8.2 player.

Another problem is that when I open itunes, it only recognizes the music I purchased from amazon (an not the thousands of other albums in my collection) furthermore, when I click on the songs to play, it gives me this message ?the song ?abc? could not be used because the original file could not be found. Would you like to locate it??

This is the message I get for thousands of songs.. Although I know how to locate them individually it would take me years to do this for every single song! Does anyone know a better way?

Thanks
RJ