I just purchased a aspire

Question

i just purchased a aspire 5315-201G08Mi model ICL50it asked for a username which i created. it then asked for a password which i created. it then began startup procedure. my username appeared automatically and it then asked to type in password. it won't accept my password saying its incorrect even though i am certain its correct!!HOW DO I RESET PASSWORD AS IT ASKS TO INSERT SPECIAL DISK WHICH I DO NOT HAVE AND NOTHING ELSE CAME WITH NOTEBOOK WHEN I PURCHASED IT FROM HARVEY NORMAN OSBORNE PAK WA NEW!PLEASE HELP AS I CANNOT USE IT WITHOUT GETTING PAST PASSWORD SETUP STAGE!!!!!!!!!!!!!!!!!!!!