My security product of choice is Comodo Internet Security for Windows and Linux computers. During installation of Comodo, it prompts the user to let it change the browser’s home page to Yahoo. If you do nothing, it gets changed so the installer has to click the box to stop this action.
I had this annoying issue cause a problem with a client’s web browser this spring. They needed a security product to replace their poorly-performing one on a Windows computer. I installed Comodo and when it came to the alert that the home page was going to change, I thought I clicked it off.
After the service call, I was driving to my next place and my client called to say her home page was now Yahoo and not the three tabs I had set up for them. I had to return to change her browser back to the original three tabs.
So Beware of programs you are installing that change things on your computer. Read software installation messages carefully.