They are guidelines.
My guess is you downloaded this from the 3DWarehouse…
A lot of models you find there are poorly modeled or just not cleaned up right.
You should always open Them in an empty file so you can inspect them and clean them up before use or simply discard them if it’s not worth your time…
Also inspect for excessive geometry as that can slow down SketchUp.
You can select the guidelines and delete them!
So I used “Edit Component” and the above image shows. The Purple diagonal box selection shows up when I try to select one of the diagonal line that is coming out of the spring and going TOP LEFT direction.
Then the parts themselves are also components that need to be opened for editing. Components can be nested within another, sometimes many shells deep. Try this: pick a guide line, and keep double clicking on it until it turns blue, you will have opened as many components deep as you need to get to that level.
And check out the video posted to help orient yourself.
The guides were probably used for laying out the model during construction. They are most likely of no use to you. When you learn to use guides you will make your own for your own purposes (and will likely delete them soon after use).
It is great to just jump in and start messing with a model off of the warehouse, and throw up questions as you get stuck. But taking some time to do some ground-up understanding of what the program is and how it works will save you a whole lot of frustration. It will also give you a framework on which to hang the new information, so you are building an understanding and learning faster. Aaron, Justin (SketchUp essentials) and The SketchUp School (among others) all have great video tutorials on You Tube.
Good luck–it is a wonderful program, and worth the early struggles.