How do I install applications on my htc hd7?

Whenever i go to install the free apps like youtube it tells me to sign in with my windows live id, so i made 2 of them and tried it twice but each time i try to install an app it says "can't get this info right now. check back in a little while" and when i do it through market place it says "log in with your windows live id on your computer" which i already did... any help ?