I updated iTunes, now all my music files are in duplicate???

Old iTunes worked fine, then I was prompted to update to the latest version 11.1.1.11 and all my songs are duplicated???

ie: Album One, Song 1 followed by Song 1 (again), Song 2 followed by Song 2 (again), etc. etc.

See screenshot below.

As I also have Microsoft Media Player onboard and have have most song titles saved as mp3's when i bought the laptop 3 years ago, then added my iPod 5 and iTunes to it 18 months ago. Like I said, it worked fine until this recent request from Apple to upgrade to the latest version of iTunes for Microsoft/PC.

Maybe iTunes is picking up all media files, mp3 AND mp4 (or aav, whatever Apple call them now...).

I've uninstalled iTunes twice and re-installed twice to see if it would correct it with no luck.

I've not set iTunes as the default media player.

I can't see any fixes on Apples support page so I'm at a loss...

I'm too worried to connect my iPhone to my laptop now in case it stuffs up my music files stored on it from my PowerMac.

Any tips?

Cheers! Mick Ward