I created a few particle streak with particluar and another editor moved some of the background images around and the particle systems are now gone. I can't find them any where the other editor said she tried to copy and paste some of the layers into another comp and when she came back they were gone. Any ideas
I know that every now and then, when I open a project which came from an older version of AE, or Particular, that the location of the emit point sometimes goes off the viewable screen.
Is it possible that this other editor either resized some stuff in addition to moving it, and that the effects just aren't showing in the viewable space? By "the particle systems are now gone", do you mean the actual effect on the layer, or that you can't see the effect? If you've still got the effects, you may just need to reposition the emmiters, so they show. Also you might check where the emitters are in the Z space. Maybe they're just behind something?
If not, and you're out of luck, you should make it clear to the other editor that they are to create a new, incremental version of your file before they mess around with it. You don't just come back and stuff is gone - you screw it up and try to cover up your mistake with a lame excuse. That's what incremental backup is for - it monkey proofs your projects.