So I recently switched over to a 2.6 GHz 17inch Mac Book Pro with 4GB of RAM. I am deeply in love with this computer. However, all is not well. When I power up the computer, I hear the boot tone, but then the screen goes grey and nothing happens. The sleep LED flashes 3 times in rapid succession before pausing and repeating. If I shut it down, and power it up again, holding down Ctrl-Apple-P, it boots up fine. What am I doing wrong? Thanks in advance for any assistance.