Backup Files Before Doing Full Restore, But Don't Have The Password For User Account

I'm trying to backup the pictures, music, and videos that are saved on my buddies laptop. He forgot the password for the main account and whenever I try to transfer files to an external hard drive, a screen pops up and tells me to it cannot transfer files without password. Is there anyway to get around this? EDIT: I thought maybe it would be important to add that the account that I'm using to get access to the files must not have permissions to change anything on the computer. Don't ask me how my friend figured out how to restrict himself from changing anything on the computer, but he did and this general lack of knowledge about computers, likely got in into the trouble, that now is going to require me to do a full restore.