problems signing into zune with new windows live id

I recently changed my windows Live ID.
Now, when I want to download an app from Zune I get the attached message.
It says I need to sign out and in again.
But it uses my old windows live id as the email address and I can see no way to change it.
So I can't use Zune!
Any help gratefully received.

sorry, the error message is attached here

Just sign in with your old WLID. Then go to the top right and right click on your username. You will get the option to switch users.

Thanks Ninja.
But signing in with my old combination is proving impossible. It wont recognize the password.
It's definitely the right password so I don't understand that at all.
It recognizes my old username because that comes up in the field.
But when I type in the password it says its the wrong username/password combo.
On my phone, my old account says 'attention needed'. It asks me to sign in and it's the same story. Doesn't recognize the password.
So confusing.
Now what I'm trying to do is reactivate my old account but windows live isn't working properly! aaaggghhhhg

Try recovering the password by clicking "forgot password".