After Effects Preview: certain clips not showing up

[channstephany@yahoo.com]

Hello, I'm working on a small edit with a number of small clips. It was all good before but all of a sudden when i wanted to preview the whole thing, most of my clips just show a black screen. I've tried restarting but its not working. New to after effects so it's probably just a small problem. Any tips?

[Szalam]

Without having more information, it's going to be hard to help. A screen recording or (at the very least) a screenshot or two showing us your timeline and comp window would be a good place to start.