I have an issue, I bought my Mac second hand and I am not the Administrator. I've been having weird thing happen on my computer, shutting down, restarting, and it seems to me I've been hacked.
This morning I was Google plus and it was taking ages to load, so I switched my browser to Google Chrome and it normally comes up with my email to log in, but this time I looked at it and it was the old owner of the computer. I looked at the certificate in keychain and it was September last year. The only way he could have logged in was by hijacking my computer, because I've had it for 3 years.
Which comes to Remote Desktop: I looked at the software and it's viable he's still logged into my computer via still being an administrator. I changed all the screen sharing permissions, but then they would mysteriously change back to screen sharing... I really need help with this... what do I do.
I changed all my passwords, and am using Little Snitch, to see what's going on, but I can't remove his admin account from my computer?