<font color='#000000'>If you know anyone who does phone installation or repair they will have a "tone generator" that you can hook to the ends of each wire(one at a time) & with a probe they can trace the sound along the walls. If not,you can buy these things at Lowes.
You may wish to search in the crawl space or ceiling 1st to get an idea of approx. where they could be running. I know,not my favorite thing to do either but you may find that whoever did the wiring ran them along side of some AC runs,in which case you may find the ends tied up inside an outlet on the wall. If that is the case you may not want to use them anyway.
Try getting in touch with the contractor(good luck!) who did the work & see if he can tell you where you might find the ends.</font>