itunes folder

in my default itunes folder there is a folder called "Previous iTunes Libraries" what is this and is it safe to delete without screwing up my current library?

there is also a file called "iTunes Music Library.xml" what is this and is it safe to delete?

there is also a folder called "Incomplete" inside it is "downloads.bak" and "downloads.dat" I dont' know if that was already there or if it showed up when i downloaded Limewire which I ended up deleting. Is that safe to delete?

another icon has the itunes logo with the word data in it and is called "iTunes Library" nothing happens when i click on it. I'm guessing that one is not safe to delete?

sorry, i'm just paranoid about deleting stuff. i was rearranging my mp3's and somehow managed to lose a folder with about 15 files. so i'm kinda pissy now.

anyway, i'd appreciate any help. thanks.

 

thanks for clearing that up for me.