2010 Macbook Pro won't complete Boot

For a while it would boot into the install program from the hard drive, but now we can't get it to boot into anything at all. Often times the progress bar will get stuck around the middle, but when it does go past it, the bar fills up completely but it won't boot. I tried resetting PRAM, SMC, and booting into safe mode. Safe mode gave me a panic screen, which I will post below. We have tried booting from a known good drive, from external installation media, and even an install DVD and nothing has worked so far. Won't boot into recovery mode either.