"Apple has determined that a small number of MacBook Pro (15-inch, Mid 2010) computers may intermittently freeze or stop displaying video on the built-in display or on an external display connected to the MacBook Pro. In this situation, you may also see a restart warning message before the video is lost or the display turns black or gray."
Apple have been long aware of this issue but, despite having the ability to do so, decided not to contact owners of this machine to make them aware of it.
Instead, they chose to silently implement a policy where they would "service affected 15-inch MacBook Pro computers free of charge until three years from date of purchase."
However, in the majority of cases, this issue has not manifested itself until the customer has upgraded the OS (operating system) to OSX 10.9 Mavericks and so the period of three years has already passed. The reality of this is that, since the upgrade, many users are now left with a machine that restarts itself on a regular basis (in some cases hourly) and is a source of great frustration, if not completely unusable.
Full details of the issue can be found here:
We, the undersigned, believe that Apple should do the responsible thing and offer a logic board replacement to ALL owners of the affected machines, regardless of the purchase date. The machines that we were sold were faulty from day 1 and therefore not fit for the purpose for which they were sold, regardless of whether this was apparent at the time.