I would take apart the bobbin area, like you are changing the bobbin. Clean the area, it just might be dirty. Did she say when last it worked; it could just be dirty. The next thought is it might be out of time. Call a sewing machine repair person in your area and ask if they will check it out and the cost. See if they are willing to check it out and THEN give you a repair estimate. Something tells me it is probably something simple. If the machine was out where children could "sew" with it; someone just might have moved some settings and now you get the job of fixing them. Keep the faith, most older machines are work horses and it will be fine. :)

I used to have that machine many years ago and as the other poster said it was a work horse.It was made when singer still made good machines.
Since you said it sounds like it's hitting something~~~~~~~~did you change the needle,if not you should,because it could be bent.Then try all the things the OP said and if none of them work ,take it in for service,as the timing may be off.HTH
Kathi

My machine has done the same. Like the ladies said check the bobbin, sounds like there is something clogged in there. Clean the bobbin area. Possibly change the needle I agree it could be bent. Make sure you place the bobbin in right and have the top threaded correctly. Then try that puppy again. Good luck

I agree it might have lint or thread in the runway and possibly a bent needle too. It usually sounds like it is hitting something--and probably is-- if the needle is bent. If you have a manual check out how to clean the runway thoroughly. This will involve not only removing the bobbin but the case too. As for the knee control--did you check the connections. If it's not working at all, somehow, it's not getting power. They might have gotten dislodged in transit.