Protect Hard Disc Drive with Password?

greetings everybody so this is my dilemma.
i’ve 2 Hard Disc Drive as well as the one will be the system instant messaging runing at windows 7 and the other you are just personal stuff.
we would like a plan or a thing that obtain a password to chek the opposite disk like once i leav my personal PC upon and go out and family keeps growing it of course , if they click ex:VE HAD:it require a password.
may any system help my family with that will

Try a new software labeled “hide our drives”
and try also “truecrypt” <- is effective on SEVEN:D.