OneCare popped up and said that it had "successfully cleaner or stopped the unwanted software" from impactinng my computer. Today's menu included the Trojan Downloader Bagle.BW and Sober.S worm, making the rounds yet again.
If you don't have AV software installed, you might consider running the free Microsoft Malicious Software Removal Tool.
Skip the details and download the tool
"The Microsoft Windows Malicious Software Removal Tool checks computers running Windows XP, Windows 2000, and Windows Server 2003 for infections by specific, prevalent malicious software—including Blaster, Sasser, and Mydoom—and helps remove any infection found. When the detection and removal process is complete, the tool displays a report describing the outcome, including which, if any, malicious software was detected and removed."