After trying all of the other suggestions without it starting I would ask:
When was the last time you cleaned your machine? If it has been awhile you could have a large dust bunny clogging something inside.
There is a series of videos on sewing machine maintenance and repair at You Tube, just google the subject and you'll find the series.
Did the needle break? Did the thread bind up in the bobbin case area? Take out your sewing and start to search where the problem could be.
Someone once mentioned that their foot pedal got to hot and just stopped. It started again once it had a chance to cool down. If this may be the case you may need a new foot pedal.
Also, check out if your machine brand has a website. They may have a forum page that may have useful information. There may also be a group(s) at yahoo for your machine brand to join and get some assistance.
When you get it figured out what happend we'd like to have an update, so please share, even if it's something stupid as we all do stupid things.
Pam M