@dominicm143 said:
i've saved my old model as a component, and now it won't ...
~dominic muscatella
Exactly how?
I don't know what's in your model, but try this technique which I'll explain as if you've modeled a house.
Explode. Delete everything but the top story and roof. Save as 'attic'.
Reload. Delete everything above ground. Save as 'basement'.
Continue until you have a collection of tractable pieces. You can now delete the original. (Well, save to another name: my_old_model_that_I_may_not_need.skp.)
To rebuild, File/New, then import the parts one at a time, clicking the origin. They should assemble correctly if you import each to the origin.
That will give you a collection of small, easy-to-use models. One other technique. If you move everything in the 'attic' model into a layer named 'attic', when you import you will have a single component named 'attic' in a layer named 'attic'. Very handy for SketchUp animations.