I've had the checkerboard screen happening for two years- inspired by 'reload911', I thought I would give one of his recommended hacks a try:
"The first one is to basically install FanControl and set it to 40/75 with 2500 rpm, but that's just gonna get you rid of constant lockups. Sometimes when your notebook is hot and doing some hard work it might lock up and there's nothing you can do about it. Well, actually you can..."
I had tried SMCFanControl before with no success, but I with FanControl (completely different product) I am now able to use my MBP in a limited manner: If I start up cold, it will almost always do the checkerboard thing and hang on the blue screen. I then force quit by holding power button, then reboot in safe mode. It always starts off in checkerboard, hangs a little on blue screen (sans checkerboard) but after a few minutes it will boot cleanly into safe mode. I then run permissions verify and repair, and it always comes back with the same permissions needing repair. See my log file:
https://docs.google.com/leaf?id=0B1FxmJMm-iQCYmUyOTQ5YTQtM2ZhNy00ODEwLWE0ZjQtMDZ hNmVhYzlmNDk2&hl=en
Do these recurring permissions problems indicate anything to you more knowledgeable types? I am writing this now on my MBP, and will be able to use it without issues until I put it to sleep or shut it down. I don't let it sleep, and shut it down when I am done. I have been able to use Aperture, Photoshop, and Illustrator successfully, where before these apps would cause the processor to reach temps upwards of 200 deg F. Now the hottest I've seen is in the low 150's.
I'm happy to be able to use the MBP for something, but I've been round and round with Apple to no avail, and shouldn't have to even deal with this. I feel like they know this model is a problem, which was fixed with later models (my wife is about to buy a new MBP through her university, so I hope so!) and they need to own up. To make matters worse, the f,r,4, and f4 keys no longer work (I suspect they were cooked by the processor) and I have to use Keyboard Viewer to type them. Also the battery is toast, and the DVD drive is suspect. Wait- why do I bother again? Freakin' Apple!...