Hotmail help

I use hotmail for my mail simply because it's easy and not succeptible to viruses. I've had a little problem lately though, I get attachments and when I click on them it asks me if I want to download, I click yes, then it asks me for my password, which I put in, then the attachment completely disappears. Not to be found anywhere. What's the deal? How do I fix it. It used to not do this till recently.