I did a search for this file and it is a standard file for windows. Bill Cook Just what is SULFNBK.EXE? It's a utility shipped as part of the Windows 98 operating system that allows users to restore long file names. Thus, anyone using the Windows 98 operating system would find this file on their system. If the hoax were received by these users, and believed, many might delete the file thinking their antivirus software had somehow failed to detect the virus. In fact, it wouldn't be the first time signature-based scanners failed to detect a new virus, making the entire hoax even easier to believe.