Hi, i am a hardware technician of mobile phones.never use a Apple computer in my life.but i do repairing apple phones(hardware). just now recently i brought a Macbook air 13" used one from a friend. it was leopard operating system and 80gb hdd. now i need to install a new 500gb hard disk to it and install lion operating system same like factory setting. i have lion bootable flash disk too. and i need a help from you guys how to install a new HDD(i prefer 500gb, if its not possible then please advice me with one is perfect maximux size) and install lion to macbook air same like factory. simply i can take this one to any apple center or computer shop. but i like to do it my self. i need a clear step by step detail. how to fix a new hdd.and format then install lion. waiting for your valuable reply. Regards.