that's one good idea blackh0le.. rename the .exe or .com or .vbs or whatever file to .virus or something... I usualy rename files I'm working on to .tmp it's your choice

And you might need a hex editor...
a good free one for windows is winhex.. http://www.winhex.com/

some files don't like to be txt edited (one space can make a difference)..
so I usualy use a hexeditor