Ollie, I haven't got an answer but this should take it a stage further and bump you up to the top again.
When you say "the next info box appears for a few seconds" do you mean for instance when you enter regedit, that the registry editor window appears for a few seconds. If not, what do you mean by "info box"?
If the command is executing ie in this case the registry window editor appears but only briefly, is the same happening for any command. For instance what happens if you enter "cmd" or "command"? You should get a Dos window - black background. Does this disappear too?