Same problem, same symptoms. Get diagonally squared pixels, which can morph into into multi-colred wavy lines, and shut the system down.
Brought my MBP to the Apple Genius Bar, and after some head scratching and consultations with other techs, they assume it is a bad logic board. BTW, had the logic board replaced by Apple less than a year ago. Just sayin.
My particular bump, is that my MBP is a late model (2006 17"), and Apple no longer stocks replacement parts on "legacy models after 5 years on market. My Mac is 5 1/2 yrs.old, old in tech years but has benn working fine. So no Apple supplied board for me. (sigh)
Techs advised I go to an OEM Resller-service company to replace the board as that they might stock the board. I seem to remember that there was a "law" that stated that manufactureres of U.S.produced goods keep parts in stock for their models for 10 years. But I guess that's cmparing Apples to oranges.
However, I did come up with a workaround that restores my functionality, if only on a termporary basis, (2 days to 4hours) so if you continue to suffer from the same problem, this seems to get me back to working mode for mission critical assignments.
If you experience the freeze-out and funky screen, try the following ... it seems to work for me albeit temporarily.
When yo get no response from your system, perform a hard shut down. Next, restart the computer in Safe Mode by holding down the Shift key during boot-up. Takes a bit longer, but hang in there. When your screen indicates that you are in Safe Mode. log-in as usual. Then open the Finder and got to Disk Utility. In Disk Utility, select the VERIFY DISK button (NOT the Verify Permissions button). Soon you should see the Green message that your system is OK (hopefully). If so, close the Finder and perform a Restart back in normal mode. You should be able to regain your working splash OS page and gain back your functionality ... again this is a temporary fix if you have to ger back to work.
Try it and good luck.
I had been contempating getting a "newer" MBP, but I am running OX10.57, and many of my current apps are not Snow Leopard comliant, no less Lion compliant, and it would cost another boatload of dough just to upgrade all third party apps which I frequently use. If it aint one thing it's another IMHO. (Sigh)
MacBook Pro 2.16 GHz OS X 10.57
Message was edited by: KAUFFILMS