IK Won't move bones / Armature won't connect to mesh

As you can tell by the title, this is a two-problem thread.

First problem: I’m trying to rig my model using IK constraints, but the elbow won’t move. I’ve deleted the parent of the IK bone, did everything to add the correct constraints, but still it’s like the bone’s just floating freely with no care in the world. I’ve even tried redoing the step over, and it still won’t do anything. I don’t know what to do here. (Also, when I move the hand IK, the elbow bends forward instead of backwards, as though the arm’s rotated. What’s the neutral rotation so I can check and see if this is indeed true?)

Second Problem: Even though I connected the mesh to the armature using automatic weights, the armature doesn’t move the mesh. The mesh just sits there like it would if it hadn’t been connected at all. The armature moves, though.

Also, I’m re-rigging a makehuman model if that has anything to do with it. I doubt it, but you never know.

Thanks for any help! I’m new to blender (as you can tell, these are probably easy fixes if you know what you’re doing) so I don’t really have the whole rigging thing down yet.

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