Couple of days ago I downloaded After Effects Trial (I still have 5 days left) and everything was working fine until now, as AF doesn't want to render my movies, when I want preview my animation on the timeline the blue lines stays at the start and the ed line moves, but whole video is stuck on one frame, only the audio plays, but nothing else. I even tried to open up my old files to see if they work, but they have same problem, audio works, but video doesn't. Also if I have only frames lets say each frame different colour which shows up at different times, preview play button doesn't even work. I have a mac computer and have no clue why this is happening. I also tried to uninstall and re-install the program and nothing works.
Could you share some screenshots (or a screen capture video) demonstrating the issue? Also, what OS are you using?
when I want preview my animation on the timeline the blue lines stays at the start and the ed line moves
That is how it's supposed to behave.
but whole video is stuck on one frame, only the audio plays, but nothing else
That isn't. Unless some settings got changed in your Preview panel. We definitely could use a screenshot of your entire preview panel.