I registered with the nyu hospital to access my records online, i was sent a temporary password but do not know what to use as username. ?

Accessing records: As long as your password is very secure, u can use any password u wish (especially one that's easy to remember) unless the hospital has specific requirements for user names. Often, your e-mail address is acceptable. Check with hospital if they have specific requirements for user names. And make certain your password is very secure.