I have a friend's Macbook that has a problem with the Safari browser. When I open Safari, a pop-up box appears that blocks me from going on any website - it is called savebigonsearch.info. Due to limited options and knowledge, I've used programs like Bitdefender and Dr. Web but they are unable to remove most threats for some reason.
I've taken a screenshot of it on the Mac but I can't open it on my Windows laptop, which I'm using to post on this forum. Therefore I must apologise that I cannot provide a screenshot of this problem.
The Macbook is using Mac OS X version 10.7.4. I can't update it any higher. I may need more help than usual since I am not familiar with Mac OS X.
Please help me in removing this suspicious program or whatever it is and please keep in mind that my options are limited, in the sense that I need to use a USB to transfer files to the Mac since I have no Apple ID, etc. to download any apps and no internet access on the Mac due to that program that's blocking Safari.