Bought a 1970s tissot automatic seastar watch and was ticking for two days the just stopped. Have tried winding but won't work. What is most likely the problem?

A self winding watch will run for 2-3 days if it is not worn (they thrive on being used) and it sounds as if you have not been using it; is this the case?

It could be that the winder does not operate on the spring (some watches don't), so to wind it up you need to activate the self winding mechanism.

You can do this by gently swinging the watch from side to side for a few minutes. This will simulate the normal operation when it is being worn.

If you continue to have trouble with it stopping, it could be that it needs cleaning. I had a similar problem with a watch I had some years ago.