can i file chapter 7 when I have no lien on my home

Whether the house would be sold in a Chapter 7 depends on its value and what exemptions are available under applicable state or federal law in your case.   There's nowhere near enough information to advise you on that. Also, if you've been repaying your parents' loan, the Trustee in a Chapter 7 case can sue the recipient to recover anything you've paid in the 90 days prior to filing your bankruptcy case.  That could ultimately affect your parents. A consultation with an experienced bankruptcy attorney in your area will yield the answers you seek.