The first thing I would do is download a free manual from Singer.
(free manual here). In chapter 6, it tells you how to clean the machine and how to remove the bobbin case. Clean that area carefully. Use q-tips dipped in a little sewing machine oil to clean all the crevices. I checked the manual. It does not have a function to drop the feed dogs, so something is probably either broken or stuck. Your best bet to get it working is cleaning and oiling it. Sometimes, a thread gets stuck somewhere and it's hard to find.
This machine is a little newer than the machines most of us deal with. Hopefullly, it's just dirty.
bkay