There's an INI file that contained a line like "SHELL=explorer.exe", if you changed that to "SHELL=progman.exe" it would boot up looking like Windows 3.1, and i

There's an INI file that contained a line like "SHELL=explorer.exe", if you changed that to "SHELL=progman.exe" it would boot up looking like Windows 3.1, and it worked at least as late as Win98. I had to use it once when something with Explorer got corrupted.