The main pointer is to Win9X.Now the computer users generally install the Windows system, and the Windows is generally infected with the Win9X system, the most typical of which is CIH.But this does not mean that a computer that is a WindowsNT series (including Windows2000) can be ignored.Some Windows are not only easy to infect on Windows9X, but can also infect other files on WinNT.The main file extensions are EXE, SCR, DLL, OCX and so on.