I am new to After Effects and recently downloaded it onto a hard drive that I plug into my laptop. Whenever I try to import audio by going to import>file, the audio is greyed out and I can't click on it. Also when I try to drag the audio file in, it will not drop. I have tried .mp3 , .wav , and .aiff but nothing has worked. And yes I've tried shutting it down and rebooting.
Nobody can tell you anything without exact system info or other technical details.
It sounds like you have a lousy installation. Install to your system drive, and not an external drive.