A computer virus can get into your computer if you go onto a harmful website, EG some porn sites
nah
Yep. Some viruses that infect other programs don't really care what the other program is, and will infect it anyway if possible.
I don't know what virus produce viruses, but a virus called "Downloder" can downlode viruses from Google, bing ...
From someone who already has a virus that passes it on to you by sneezing coughing, or any of that stuff if you're in a cold. But if it's not, then answers may vary.