MBP Boot Issues

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.

 

It seems to indicate a fundamental hardware issue. From what I've been able to determine, via trial and error, is that the 2 2GB memory modules installed by Smalldog as part of my order are defective. I replaced those modules with the ones that came in the MacBook Pro. Once I did that, and reinstalled OS X (how easy it was!), the notebook performed fine. So I think my next call is to Smalldog to get good memory modules.