Safari opens automatically after startup.

Hi,

I have a very frustrating problem with Safari. Every time I turn on/reboot the Mac, Safari would automatically open itself. Moreover, when I close the application (Safari) for the first time after startup, it would always open itself for the second time, making me to close the application two times in total in order to completely stop the application from opening itself.

I've reviewed some of the suggestions, however, they don't seem to work in my case.

1. I've looked at the dock icon and already made sure that 'open at login' isn't ticked.

2. I've checked the 'login items' inside system preferences>User & Groups, and Safari is apparently not there.

I'm not sure if this is related to the 'MacKeeper' virus where I found in my mac earlier, but already deleted all of them and now it seems to me that there's no any MacKeeper-related file on my mac.

Please help me with this.

Thanks