Display freezes at boot until screen moved

Question

March 2010 Macbook Pro 15 - display freezes at boot from cold.
First image is dark purple, this lightens to patchy grey with vertical lines.
Move the screen and the display changes to account log in screen, but track pointer is frozen and screen gamma rises until display is whiteout with vertical lines.
Freeze and whiteout can last up to 90 seconds now, freeing for a fresh display each time screen is moved then freezing again.
Problem getting worse - lasts longer and now occurs on wake as well as boot.
Have updated everything, checked for malware, cleaned all app content, run disk utility/ repair, hardware check, reset permissions, reset PRAM, reset gamma, reset SMC - not helped. No history of damage!
Took to Apple - they replaced logic board and graphic card - problem not fixed.
Any advice to give me to give them when I go back to the bar?
Thanks

Answer 1

Empty,Blue Screen.
http://docs.info.apple.com/article.html?artnum=106464
1. Start up in Safe Mode.(shift key at startup)
a. Drag the Fonts folder from the Mac OS 9 System Folder (not the Mac OS X System folder) to the desktop.
b. Drag the Fonts folder from ~/Library/Fonts to the desktop.
b. Restart the computer in Mac OS X.
c. If this solves the problem....you have a corrupt font in one of the above font folders
2. Remove incompatible third-party startup items.
a. Start up in Safe Mode.(shift at startup)
b. Open the Mac OS X hard disk.
c. Drag third-party items out of ....
/Library/StartupItems .......
/System/Library/StartupItems ... Place them on the desktop .... If you're unsure whether an item is a third-party item or an Apple-installed item, don't move it.
d.Restart the computer.
Note.. If this resolves the issue, add the Startup Items one at a time until the symptom occurs again. That way you'll know which one is incompatible. Repeat these steps and remove the incompatible item.
george