I'm an oldtimer to litestep and im wondering if the flags to Litestep.exe still work. Have you tried hitting CTRL+Shift+ESC, then go to Applications tab, [New Task...] button, then type in or find C:\Path\To\Litestep.exe and add -uninstall to the end.

ex.) C:\Litestep\Litestep.exe -uninstall

I'm not sure if this is still works or even helps since you want to do it from a different user, just remember you have to have admin priviledges.