Adobe After Effects Help :(

Hi guys, I just recently had a user donate me an intro for Adobe After effect, well, he showed me how anyway, and I got it looking really spiffy, and when I try to publish it, it takes a good few hours to finish what ever it is doing.
So, that was fine, but now whenever I try to play it, it is as if I am watching a 1080p video on a windows 98. It runs at 2 maybe 1 frame per second.
Does anyone have any suggestions?

Is the software a legitimate version?

I've used After Effects at work on computers far less superior than my own, never had any issues like that.

Yep, the key worked for it an all, I got it a few weeks ago, and am just now getting into it.
I am starting to think I am publishing it wrong, I am saving it as a movie, and it plays so weird. :/