Afori is not a dangerous memory resident parasitic virus. It hooks INT 1Ch, 21h and writes itself to the end of .COM and .EXE files that are executed.
A Virus.DOS.Afori.656 infection can be as harmless as showing annoying messages on your screen, or as vicious as disabling your computer altogether.
Depending on the system timer the virus drops the letters on the screen like the Cascade virus.
Other details Edit
The virus contains the text string: