Hey guy's, I found the problem! When the 767 was installed, it deleted an FX file that FSX uses for the aircrafts lights. I found this info on Avsims forum. You must find the file fx_2.bmp and put it back in Effects/Texture folder. This brought back the red beacons, white wing strobes, red and green position lights, and white position lights. See if this works for you! It worked for me!