4 or 5 hours for rendering could be completely normal and expected. Render time depends entirely on what you are doing in the composition, what format you have chosen, what the frame size is, what system resources you have available. My really complex compositions have a design limit of 7 minutes per frame for rendering, but I have simple comps that render at the rate of several frames per minute or even a few frames a second. It all depends.
Not playing the whole video in preview is also a common newbie expectation. It's just not going to happen unless your system is up to it or you make adjustments to the resolution of the comp panel (set it to auto for best results) and the magnification factor of the comp panel (set it to 50% or less) and the number of frames skipped, which can be set in the Preview Panel.
If you are new please start here: Basic AE. After Effects is a very complex program with zillions of combinations of switches you can throw, that does not behave the way any other video editing software does so you can't really just open up the app and dive in with any success. AE is also not designed to edit videos, it is designed to create visual effects shots or composites or motion graphics that you cannot create in an editing app. Most of my comps are under seven seconds and have only one shot. On a rare occasion I'll create a composition that covers a whole sentence of dialogue or a whole phrase of music.
Particles slow things down a bunch. Audio spectrum is also slow on some machines and can be even slower if your original audio is an MP3. Video expects 48KHZ 16 bit PCM Stereo Wave files and that's what you should be using in AE.
I hope this helps.
Hey there thanks for the advice, but would you have any idea why the audio wouldn't work after the video had been rendered?
Sorry for this audio issue. Did you ever find a solution? Please let us know if you have or if you still need help.