Daniel, I have a quick question: when you were having this problem, how did you open After Effects? Literally: what did you click or type to cause After Effects Render Engine to start?
Also, what operating system and version (ex., Mac OS X 10.10 Yosemite, or Windows 8.1) are you using?
We have recently seen an increase in the number of people who ask this question. There are multiple ways you can start After Effects, so I want to understand how you got from point A to point B.