Getting your firewall and virus protection up to date is one important thing. But the only thing to do to keep virus off your back the next time (when it has been modified) is to upgrade your Windows to the latest service pack. This is not a virus that travels in email attachments, but directly attacks and changes the port access. This attacks a know weakness in the Windows operating system, and the only way for "durable" protection is to download the upgrade service pack. Windows 2000 should have Service Pack 3 or higher (there is a 4 since last week).