iTunes, Deleting library

[vim147]

is there another way to delete all my music in iTunes library ?

Ive tried with highlighting all the albums and deleting but because I have 3500 albums, the Mac mini just freezes with the spinning beachball.

 

[arw]

Normally this should be fine. It can take several minutes until iTunes is responsive again.
You could select and delete smaller portions (a.e. 1000 albums)
If you don't need your settings, smart playlists etc. you can just delete your whole library (after closing iTunes delete the iTunes folder in <yourUserName>/Music/iTunes). When you open iTunes again, a fresh library will be created from scratch.