My RPi2 boots fine, but after some time, which can be anywhere between 15 minutes and 6 hours, it crashes, leaving both the ACT and PWR leds on. My wifi card's led is either off or stuck after the crash. Also, the crash only seems to occur while I am not using the Pi, it has never happened while I was using SSH.
/var/log/syslog:
Oct 10 12:17:54 raspberrypi mysqld: InnoDB: Restoring possible half-written data pages from the doublewrite
Oct 10 12:17:54 raspberrypi mysqld: InnoDB: buffer...
Oct 10 12:17:54 raspberrypi avahi-daemon[2647]: Service "raspberrypi" (/services/udisks.service) successfully established.
Oct 10 16:49:59 raspberrypi mysqld: 151010 16:49:59 InnoDB: Waiting for the background threads to start
It crashed at 12:17:54.