It beeps after a few seconds of sewing... four sets of two beeps

SOURCE: why does my ce-200 beep every few stitches?

I was having this problem for two days so I just called Singer and got a solution!  I'm posting it for you because I was on here looking for a solution to the problem and nobody had posted one.
Take the top thread out of the machine - cut it back by the spool and pull it out through the machine the way the thread goes when you are sewing - you don't want to be pulling the thread back through the machine because dusty bits are getting stuck up in that part of the machine with the frosted plastic where you have to make sure the thread is pulled into when threading.  You might not think there is dust in there - I didn't because I had taken that part off and brushed it out but that didn't work.  What you need to do is floss that part of your machine.  Get some dmc floss or some UNWAXED dental floss and pull it into that part of your machine - under the pieces that are under that frosted plastic part on the top of your machine - now floss it back and forth for a good 30 - 45 seconds.  When you are done that pull it out to the left - the way the thread goes when the machine is sewing - remember pulling the thread back the other way will get fuzzies stuck in there.  I rethreaded the machine carefully and made sure that the thread got pulled into that top part properly - the lady on the phone said it may feel differently now that its been cleaned out.  Then it worked again!
I hope this works for you!