no disc and forgot the password

Hey guys i just bought my friends Mac and it didnt come with the install disc and he forgot the password, reason he sold it to me ;D , for the user not the master password... But i want to keep all his software he installed and music on itunes.... How do i reset the password without deleting everything.. and if i do reboot everything will it delete everything... Sorry for the dumb noob questions lol but I am new to the mac world and need some help... Any help is greatly apprecitated

Thanks so much

Hi, it's a bit of a predicament you're in.... maybe this link will help.

let us know....