How do I set music as ringtones on my Samsung Intensity II?

[synyster]

I don't want to buy music, or buy new ringtones, I want to take music files off of my computer, and set them as ringtones on my phone. I have a Samsung Intensity II.
How do I do it? I've tried everything..
P.S.
I can't send or receive pic/mp3 messages, or access the internet.

I'm trying to do this strictly by connecting to my computer.

[Unregistered]

1.Plug you phone into you computer
2.Select "USB Mass Storage Device"
3.Select "Open Folder to View Files" on your computer.
4.Open iTunes or you music library on you comouter.
5.Click and drag desired songs to "my_sounds"
6.Disconnect phone
7.Go to "Media Center" on your phone
8.Go to "Music and Tones"
9.Go to "My Sounds"
10.Go to desired song and "Set As" and "Ringtone"