downloading problems

It's me again, lol. Um, I'm having a problem with downloading textures and brushes and that sort of stuff. It's not that the downloads don't work, it's just that every time I download stuff like that my computer gets viruses and crashes. It's happened a ton of times now and I just don't know what to do about it. We've had virus protection and all that but it's not doing much because the same thing keeps happening. Can anyone suggest a solution to this problem?