Laptop ownership

Question

I bought a Tosh laptop, set my self up as main user, then let my son also set up a user account. My job provided me w/a laptop, so how do I change my main user account, delete his user account, & let him use the tosh? I plan to take advantage of BB sales for a portable Harddrive to xfer my files [music-fotos] & then totally delete them, & also my son's files, also x-fer.

thanks
it has 1G ram, 160G HD