How to unlock my Apple ID

If your account is disabled then you might be able to re-enable it via this page : http://appleid.apple.com, then 'reset your password'

You might then need to log out of your account on your iPad by tapping on your id in Settings > iTunes & App Store (Settings > Store on iOS 5 and below) and then log back in so as to 'refresh' the account on it.

For your security questions, if you have a rescue email address (which is not the same thing as an alternate email address) on your account then the steps half-way down this page will give you a reset link on your account : http://support.apple.com/kb/HT5312

If you don't have a rescue email address (you won't be able to add one until you can answer your questions) then you will need to contact iTunes Support / Apple in your country to get the questions reset.

Contacting Apple about account security : http://support.apple.com/kb/HT5699 (you can also try this link if you can 't get your account enabled via the above)

When they've been reset (and if you don't already have a rescue email address) you can then use the steps half-way down the HT5312 link above to add a rescue email address for potential future use