Crashing without reason

[Mel38323556sghw]

Using after effects used to be incredibely easy. I would use very complicated comps and 3D room building and plugins constantly, 3D texts etc. I have done way more complicated projects and it's worked perfectly fine. But recently all I'm trying to do is import previously rendered mov files into the timeline and it won't even play. Disk cache is empty. My performance settings are at where they should be (or at least they've never changed from what worked well for me before).

I got irritated and thought maybe it's the project file itself. So I rendered everything I had so far, created a whole new project and imported the rendered footage. And it still can't play, pre-rendering is not working (glitches and breaks). I get RAM errors when there's nothing wrong with my RAM. Pressing play doesn't work sometimes. Sometimes the audio breaks and doesn't play. I have to turn the entire PC off and restart for the audio to work again. And it'll stop responding and force close when I try and move the blue arrow across the timeline.

I have no idea what the problem is. All drivers are updated. 

[ToolfarmJP]

If you use old third-party plug-ins,  you turn off "Enable Multi-Frame Rendering" (Preferences > Memory&Performance).