Same here. Early 2012 MacbookPro running Lion (10.7). First appeared randomly about a month ago. During normal (not heavy) use the screen will go a solid blue colour and the machine requires a restart. The first few times it recovered straight away, more recently it's become the 'white(/grey) screen of death'. Boots to usual Apple logo with spinning timer, but then progresses to the white/grey screen (no pointer or anything) instead of the login screen. Tried all the usual recovery methods:
Reset NVRAM/PRAM : boots to white/grey screen.
Reset PMU : boots to white/grey screen.
Safe Boot (Shift at startup) : boots to blue/black vertical stripe screen
Hardware Test : booted to white/grey screen for first 20 attempts, then eventually boots to the test app which reports no problems.
Recovery Partition : boots to white/grey screen.
Internet Recovery : finds network and runs the process, then boots to white/grey screen.
Boot from Snow Leopard on a USB stick : boots to black screen.
Boot from Ubuntu on a USB stick : boots to black screen.
Netboot : boots to white/grey screen.
Boot from MemtestX86 CD : boots into app. Left tests running for 72hrs - no errors detected in RAM.
Boot in single user mode, run /sbin/fsck -fy (some minor repairs completed) and reboot : boots to white/grey screen.
Boot in single user mode, mount the volume, create a new temp directory and copy all NVidia drivers there then reboot : boots to white/grey screen.
Boot in single user mode, mount the volume, move NVidia drivers back to their original directories and reboot : SUCCESS (for a week, then screen goes blue and we're back to square one)!
Last thing I'm about to do (when the FW800 cable arrives) is to target boot and use another Mac to drag the data from the drive.
Come on Apple, fess up and acknowledge this known issue with the NVidia GPUs. It's a heat problem primarily, and it needs to be resolved in the first instance by replacing all the faulty hardware you sold and have continued to sell since this problem first came to light in 2008 as this article shows: http://www.tgdaily.com/hardware-features/39045-nvidia-gpu-failures-caused-by-mat erial-problem-sources-claim
Mac user since 1986 and I'm thoroughly brassed off about how cheap and shoddy the hardware has become over successive recent generations. I'm still running a Powerbook G4 at work which is soldiering on relentlessly not to mention a Mac IIVX which is controlling some very very old hardware. Neither of those Macs have suffered such poor component and build quality issues.