Acer Aspire One netbook (linux) asking for pword (unix or something)?

Ok so i need to update it and everytime i try it asks for a root pword for privilages, like wtf i never ever set a pword, and ive been seaching EVERYWHERE but everythings so technical and so computerised for me. I learned to change it open a terminal window, and type sudo it says its changing pword, but then asks me for my current unix pword, and i dunno what it is. IVE NEVER EVER SET A PWORD FOR THIS NETBOOK (it doesnt have log in passwords either cuz it logs without password). Can someone plz help me this is really frustrating man, plz helP!!!!!!!!!!