Okay. Have you tried booting into “Safe Mode?” That usually gets the job done. Resetting the PRAM works sometimes too… as does just holding option to select a boot sector… There are a lot of things to try. Did the DVD come out when you told it too? Was there anything on the DVD? I know you said it was blank, but I have had my mac tell me something was blank, but it had old windows information on it. (By the way, incase you don’t know how: To boot into Safe Mode on a Mac, hold down the Shift Key right after you turn the computer on, but let go right after you hear the beep. Reseting the PRAM is different for every version of the mac, you’ll have to check apple’s website to see how to reset yours, and if the DVD is still stuck in the drive, press and hold the mouse button to get the DVD back.) One last note, I just thought of: Does the grey screen have anything on it besides the Apple Logo?