This virus is capable of infecting in both Windows 9x and Windows NT 4.0. It infects all Win32 type (PE) files, such as .EXE, .SCR, and .OCX in the Windows and Program Files folder including their sub-directories. The virus also searches for all Shared Network Folders with write access and then infects files in them.

Antivirus software will cleans and removes this virus except for the dropper file.

This virus infects system files and as those files are in use while booted to Windows they cannot be cleaned, one example is EXPLORER.EXE. You need to use the Emergency Rescue Disk (ERD) to clean these files. When using the ERD, add /A and /NOBKUP with the /V and /C options to scan files with special extensions.
The dropper file FCLSS.EXE must be cleaned manually by following these steps:

1.Reboot your computer using a clean boot disk

2.Search and delete the dropper files from the Windows systems directory (c:\windows\system) and its sub-folders

3.Re-start you computer to boot back to Windows <