I have a dvd player built into my tv and until a few weeks ago worked fine. Now when I put a dvd in it tries reading it, i can hear it spin, then after a few minutes stops and says "incorrect disc." How do i get it to read them?

The problem of dvd is the optical lens it's just dirty, first try to use a cd cleaner if doesn't work you should do it manually. Unplug your unit first then try to remove the cover of your unit but be sure to remember all the parts location, then you should use a cotton buds then wipe the optical lens very gently but be sure not to touch your optical lens. this may help you thank's.

In most cases when the CD does not play it is possible that the optical head is a suspect. Sometimes it might pick up ordinary audio CD but will not play other formats. This indicates that the optical head is weak and so there is no detection or scanning of the CD . If the optical is working the tracks will be read immediately but with no scanning the laser head can be defective.

The main motor will not work in some cases as unless the tracks are read the drive motor will not work with signal from the processor.
Sometimes certain cleaner disks will not be tracked to run for cleaning as it will not be read and so will reject. Hence it is ideal to manually clean the laser head eye using a cleaning swap /cotton bud with gentle pressure on the lens eye.
If there is no result then watch if the CD spins or tries to spin. If so the board seems to work unless a test is taken on the main board but the possibility of a defective optical head can be the suspected fault.
If any of the above seems otherwise we must recheck with possibilities of a malfunction of the main processor board