I have the Simplicity SE2 which is the japanese twin of the PE150. Did you break a needle or hit the hoop earlier in your stitch out? It sounds like the timing may need to be reset.Reassemble the bobbin case. Take a magnifying glass and a good light and hold it up to the bobbin case and turn the wheel so you can see the the needle come down and pass in front of the hook.If it is not correctly in line the it will not pick up the thread. If there is a burr on the throat of the face plate this too may cause trouble.Get some emery cloth to smooth out the rough spots on the plate and inside of the hole. Let me know what you find.Go to this site they sell books on machine repair but offer a free 7 point lesson on maintaining your machine and instructions on how to reset the timing of a sewing machine. It describes how to do this for each different type of bobbin case. If you can take one apart you can surely use this information or find someone who can help....family or friends who know a little about mechanical things...Good luck Oh yeah make sure that your needle is inserted correctly. Or change the needle.I know that sounds silly but it may bent .