I've solved my issue through reassigning a path, without changing the "from" box. I can't find where that function is now, but that is how I did it.
You should make some note when doing things like this to a) easily find what you did again, and b) make it easier for us to try to understand what you did.
I going to make an assumption that you relinked you music files. File > Library > Relink Music File Paths.
Then I managed to delete PLAYLISTS from the bar at the top. Don't know how. I've looked through every setting and can't find how to rectify that. I may be able to go into my old laptop, save the settings file and import that to my new MB, but that's admitting defeat, so any help with that greatly appreciated.
A screenshot may help us with this. Again, I am assuming you right-clicked on the playlists tab and then clicked 'close tab. Did the playlist tab show all playlists, or only one? Do you see a list of your playlists in the left sidebar?
...read all the instructions online.
This is probably the best advice to follow. And since there are so many settings, options, and views in MB, it's often difficult to know what a user is referring to. That's why screenshots help tremendously.
I should also note that if you copy the settings file from the old installation, the paths to the files should be the same or else you'll have to relink everything.