How to repair my Kenmoore Model 385.16221300 Sewing Machine ?

This is a great machine. Had it for many years with never a problem...until NOW! I read the manual, did my troubleshooting, but it is not working. The bottom thread bunches up and within a few stiches the machine is jammed. Have to tug and pull to get the thread to break loose. It seems the top thread is tangled up with the bobbin thread and is wrapped around the bobbin casing. Any suggestions, greatly appreciated!

Thank you,