I have a 4 year old Mac Book Pro with the dodgy graphics card...
Yesterday evening the MBP froze. I was able to ssh in to the
rascal and did a reboot.
The system would fail ( gray screen) during the boot.
Fortunately the clone I made the night before would boot, so I
did a smart copy back to the main disk from the backup and within
a few minutes I was able to reboot from the main disk
Life is good...
Jerry