Virus Problem

[M|ch]

i have a friend who is using Mac, and he is using Mac messenger, the problem is that sometimes when he is offline he send me this : " I have been taking Acai tablets now for two months and already lost 36 pounds, it is the same stuff that was on oprah and cnn," with a link for a site.

if im on this computer or the other its the same he always sends me this , and sometime i see him online , i call him he tells me no it wasnt me LOL. and everytime i open messenger i always get ads from him like the one above.

i told him about it , he told me its ur pc because he is using Mac and theres no viruses there.

so whats the problem , is it from my pc or his, cuz i dont think i have 2 pcs infected with the same virus Lol

[Sheriff Ice]

there is viruses on MAC who said there is not?!!!

but the MAC viruses are not spread as Windows viruses.
Why would a hacker creates a virus that will attack less than 5% of PC users he would prefer to attack the other 95%