Why is there no virus in Mac computers?

On the commercials it said that there is no virus in Mac computers, but there is on windows computer, why is it like this? Why can't windows have no virus as well?

Why is there no virus in Mac computers?free antivirus

When you click on a file in windows that has a virus it automatically installs without you doing anything else and your INFECTED.

Mac and Linux needs your permission to install programs on the computer. this helps eliminate virus getting on the OS

Mac and Linux do have virus but not as many as windows.

I guess if the Mac was more popular than windows I guess there would be more virus out there for the Mac.

Windows Vista the new OS that is coming out on Jan 2007 do have this option where it will ask your permission (and password) for you to install programs or modify the system.

Why is there no virus in Mac computers?internet

Do you trust commercials? Even John W. Thompson's computer may have viruses.
I'm guessing because people don't waist their time writing virus for Mac computers since the vast majority of private and companies use Windows.
Macs have no virus's lol. that seems highly improbable.

they aren't as common as windows systems. So they might have less virus's but none you got to be kidding. Why would they say that when it's not true? They are trying to sell their product the tell you want you want to hear. Macs are alright don't get me wrong.
It is said that Mac computers have a built in safe guard, that does not recognise a virus. This is a myth, a mam on here bought one and said it is not true because his computer got a virus.
because the windows system is very popular,and if any one who wants to make a virus,he will design it to work on windows system,because he also wants to spread it isnt that right?.very few people use mac system(comparing to windows users).