Wow, someone still uses Windows ME? That was the last version of Windows that ran on top of DOS.
System Restore was introduced with WinME. I believe it was turned on by default. If it's on and you boot off a CD, you might be able to do a manual restore (not sure if the instructions differ for ME). It'll be a bit tedious from a command prompt, but it sounds like you have nothing to lose.
https://community.spiceworks.com/how_to/214-perform-a-system-restore-manually-when-windows-is-not-bootable
Restoring explorer.exe might work if your problem is explorer.exe has become corrupted (it's the default "shell"). But usually problems like this are caused by a virus which attaches itself to your system and sets itself as the default shell. Simply replacing explorer.exe probably wouldn't fix that. You can try scanning the WinME partition with a virus scanner from another OS. If the peculiarities with MBR and primary partitions may make it impossible to view the WinME partition from one of your other OSes, an antivirus boot CD should work.