Symantec is warning users of the new trojan horse that phished Microsoft's Windows Genuine Advantage.
Users should KNOW that activating a copy of Windows is free (online activation or using some toll-free numbers).
If ever you see got that Windows asking for credit card information to activate the copy of Windows, DO NOT enter your credit card details. Run a scan using antivirus or antimalware program. You're maybe infected with Trojan.Kardphisher!
More info can be found here
http://www.symantec.com/enterprise/security_response/weblog/2007/05/ms_needs_your_credit_card_deta.html