AE project not rendering or caching preview

First, purge all memory and disk cache using the Edit menu. 

If the project crashes and the render fails at the same point, or even close to the same point, select all the layers in the comp, press the U key twice and look for everything that you modified in all the layers at or around that time. Try turning off effects or resetting values one at a time until you can run a ram preview from that point. That should tell you what is causing the problem.

If you can get the comp to preview and it still crashes using the AME, then try using the Render Cue and the Output Module's default Lossless preset to render a digital intermediate that you can add to the AME and render your deliverable file that way.

If you can't figure it out we need complete workflow details and screenshots showing the modified properties of each layer. Embed them using the toolbar on the forum. Without workflow details, it is impossible to even make a guess.