How to Delete Duplicate Songs on Itunes

I just uploaded my songs from an external hard-drive to my macbook and when placing the mp3 files onto the itunes, they all double up making me have near 2000 songs. I do the view>show duplicates, but it just shows them all. I have tried scripts but I cannot get one to actually deleat them instead of moving them around. Is there a way to do this without clicking and deleating songs 1000 times?

Also on the external hardrive they are not doubled up, but they have a folder for each song

Example: Red-hot Chili Peppers>Albums>Songs (Which are not doubled)

I do not know why they are doing this I have tried many tricks from what I have found online all are unsuccessful..

Go to View>Show Duplicates and move all those to a playlist, then run this program.(half way down "remove duplicate tracks)

I did that exact same thing. It said no duplicates were removed. But I must of installed the script wrong.