Hai
  you can divide your desktop in to 4 screen in which each screen act as a new start.
  you can open 4 different windows in each screen.
If you want to download it use the above google search in the top of blog.
You can download it from the below url
http://dexpot.de/index.php?id=download

   Here you can enable as    run at start up,by using this you get an experience of handling 4 computers.