Mac Air Book problem with password?

My Mac Book Air was a present from my daughter in Australia and she wanted to drag me into the 21st Century !! It all worked fine and I never ever used a password but now a white square appears on a blue background with the apple logo MAC OS X and then my name's Mac Book Air a picture of a parrot and a box asking for a password? Despite attempts it seems to shudder and the only options are sleep restart and turn off. I have never used a password and have only recently established my Apple ID. She sent me this as it was purchased in 2008 and the warranty and support is now finished but I am still an Apple Customer and wondered if there was anything that you could suggest plesse? I actually feel like the parrot and hope you experts can assist me !! My Kindest Regards