Okay, I upgraded from 1.3 to 1.4, also updated the definitions from 12/29/06 to 1/5/07. Then did a Recover to undo the fix that S&D 1.3 did on 1/3/07. This restored the value "C:\Windows\System32\Rename.exe" to the registry keys HKEY_USERS\S-1-5-18\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\ and HKEY_USERS\.DEFAULT\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\. Finally, did a scan using 1.4 and the latest updates, which showed no problem.

Thanks to all for the helpful information!