I have a Hp Envy 15 running windows 8

I have joined a homegroup but as of this morning I am unable to access any of the shared files or re-join the homegroup.

every time I try i keep getting the same errors

1. Unable to join a homegroup
--> (run troubleshooter)
---> Network related issues
----> CMD (admin) Ipconfig/ release & renew
same issue...

not sure what else to do or why this keeps re-occurring