I have a computer with two systems, one is Windows, the other is Ubuntu (installed by my boyfriend). I may have clicked on something and downloaded a malware from the Internet. My homepage was changed to Cassiopesa Search without any knowing. I found this post and took steps to remove add-ons on three browsers (Internet Explorer, Firefox and Chrome) and system files as well. But the question is that I have shared a file before I notice the malware to the other system (Ubuntu). My BF does not know the infection yet. I wonder can it affect the system? And how?