Do you mean that your iTunes account is disabled ? If you do then you might be able to re-enable it via this page : http://appleid.apple.com, then 'reset your password'
Or you might need to contact Apple : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page
If it then works on your computer's iTunes but not your iPhone/iPad/iPod then try logging out of your account on that device by tapping on the id in Settings > Store (Settings > iTunes & App Stores on iOS 6) and then log back in and see if that 'refreshes' the account on it
If you mean something else ... ?