I have tried all the obvious commands at boot without success, including Safe Mode. Then booted into Single-User mode. Ran “fsck -fy” command. Shows 9 line item warnings: “time stamp is invalid. Is greater than current time”. Rebooted and ran a hardware check which showed the battery needed to be replaced. Will replace the internal battery today, but not sure how to reset the date in Single-user mode. Any thoughts?
Cmd-V
while booting. See if you can see what messages appear on the screen. Also, can you boot to Recovery?