Want to make money!?? - Virus

I am posting it so that you can avert something that my friend caught up with today. Today, as he opened his Yahoo messenger, he had a message from his friend. His friend had referred him to a URL to make money from Internet. My friend usually hates SPAM, but since this was from his friend, decided to click on it. And here it goes, his computer got infected with Trojan. When I checked my account after this, here it was - a message from this friend with a referral to the same URL. If only I had clicked it(which I would have, had I not known it in advance), the virus would then be spreading to my friend's computers as a message from my account. This virus seemingly disables task manager and other activities. Get your computer anti-virus updated immediately and do not click on any link from your friends in Yahoo messenger.