I have attached a blend file (not made by me) of a galaxy made from particles. I want the galaxy to look like and stay as it is in the Frame No. 1. How can i stop the particles as the timeline moves so that the galaxy retains the shape and particles dont move. I have tried making the "ALL" and "GRAVITY" in forces to zero for all particle systems, but it doesnt help.
I want the galaxy to be static and move a camera from far into the galaxy. Hence need it to be stationary. Please help.
All your particle systems have the default velocity settings, which is 1 m/s in Normal direction. Of course they move - you have to set them all to 0 m/s or even better, set Physics to None instead of Newtonian, then you don't have to disable Gravity or All forces.
Another thing I noticed is that all particles have a lifetime of 50, which means (since they are all spawned on frame 1), after frame 50 they will disappear (your animation end frame is set to 250), because under Render > Extras you haven't enabled Dead.
This is also a way to have them not move or react to forces: Set lifetime just to 1 and enable the option to render Dead particles. Then they stay where they were born but still show in render.
Here's an overview of the settings I mention which you could / should change:
