when i go to control panel to check on my homegroup password (in my main machine), it appears that i do not have a homegroup passwrod. probably never set one up or knew that i needed one. is it possible to set up the homegroup passwrod after the fact?

You can set/change the password as described in the following tutorial: http://www.sevenforums.com/tutorials/44002-homegroup-change-password.html Hope this helps.