hello everyone my name is omar, i need help with this mac i purchased. i met this guy online on craigslist he was selling this imac 21.5 desktop 2.0ghz etc... so he told me the system had a pw and he didnt know it. u can still use the computer but u cannot install things, make serious changes etc.. without knowing the system pw or login. so he said if i purchased the snow leopard disc i will only have to hold down option at the start up of the desktop when the disc is inserted and just wipe it clean. the system ofcourse is running snow leopard. i did what he said and when i went to restart the system i then held down option with the disc already inserted and instead of the apple symbol popping up a pad-loc appeared. still asking for a pw. i then searched online to see if anyone could help and sum1 suggested that i need the leopard installation disc and not the snow leopard, and that the snow leopard i purchased was only an update. is this true can anyone help? also when i purchased the snow leopard disc at the apple store they assured me it will work.