You may Select>Object>Open Paths, or whatever is closest, and then deselect whatever is unwanted.
Command A will select everything on the page, but that would select shapes, too, not just lines.
Open Pths might not be what the Op wants i they want only straight lines or line with only a beginning and end point.
You might see if Rick Johnson has a plug in or perhaps james will stop by i think he might have a script or go to the Scripting Forum and or the Adobe exchange to see if there is a script or plug in.
I think I figured it out using the magic wand and setting the tolerance really high.