I clicked a link (turned out to be Breitbart) that said "your Flash is not updated", despite the fact that I just installed it yesterday. The two choices were "Update" and "Ok". Strangely, there was no ability to simply dismiss the popup without clicking one of those buttons. I should have force quit Safari, but instead I clicked "Ok". Then it tried to download something! I immediately dragged it to the trash, but when I tried to empty the trash it said that file was in use! I don't recall clicking on it or giving it any instructions to open so I immediately pulled the plug on the computer. I was able to delete it once I restarted.
1) Why did the computer download software from a random site without being given permission?
2) Why did it say the file was in use when I very clearly did not open it up?
3) Can the Mac actually install this kind of garbage without my permission?