I am so glad I read this thread. It's like a troubleshooting guide. I have learned.
1. If it doesn't sew, try rethreading the thread and bobbin.
2. Look to see if there is fuzz in the bobbin.
3. Make sure the needle is put in the right way.
4. Sew a stitch if your feed dog doesn't go down.
5. Don't put the bobbin in backwards
6. Not all bobbins are equal.
7. Make sure you put the walking foot on right.
8. IT'S PROBABLY NOT THE THREAD CUTTER. haha
I've had most of these problems, but I'm sure I will have a brand new one some day.
I LOVE THIS SITE.