Try Ctrl-Shift-Escape. This usually brings up TaskManager. From there, you can see if your shell is running (either explorer.exe or litestep.exe).

If not, you can select menu option File / New task. Browse to your litestep folder and run litestep.exe or to your Windows folder and run explorer.exe.
To set your shell, you can run the "SetShell" program (or your own shell manager tool). Browse to the utilities folder in the Litestep folder. Run SetShell.exe with the shell you want as a command line parameter (e.g., "C:\Litestep\utilities\setshell.exe c:\litestep\litestep.exe" )

If your shell *IS* running already, then one of the really smart guys will have to help...