I have a MacBook Pro 17" Mid-2010 that has been working fine until yesterday when it started booting to a blank, grey, screen. I have switched the optical drive for an MCE optibay with an SSD. The HDD is a 750GB seagate. I have tried: 1. PRAM reset 2. SMC reset 3. start using the alt-key (I have one system on the ssd, one on the hdd, but the startup disk selector doesn't show. 4. safe mode 5. verbose mode 6. I took out the SSD as well as the HDD and put them in an external chassi. They booted fine on the other computer. 7. I tried cmd+r for lion recovery. 8. I tried booting from an external hdd that contains the lion disk image. 9. I tried using the supplied snow leopard disks in the optical drive (after i put it back. 10. apple hardware test disk Nothing so far works. Just stuck at the grey screen. I haven't started unscrewing it all yet but just removing the bottom lid all cables seem to be attached. What else can I do? Any help would be greatly appreciated.