So I took an old computer from a friend and turned it into a media server. I took out the stock RAM and installed 16GB's. Everything was working fine on the computer except the superdrive. The drive wouldn't work and would occasionally make a lot of noise, as if it was trying to play a disc, it would last 30 secs and then go away. This wasn't a big deal at all, I didn't need it for anything. But, idiot that I am, was bothered by the noise. I wanted the noise to go away. So I took out the superdrive, I didn't replace it with a new drive or an additional hard drive, just took it out and closed up the back. Now I'm not getting anything. All I get when I turn it on is the grey screen. The progress bar show up at the beginning but stops about halfway through and then disappears as the screen goes grey. I can't get it into Recovery Mode. Does it need the SuperDrive to boot up? Did I do something else while removing the drive. Visually nothing is obviously wrong. Wondering if anyone has any thoughts or ideas?