Fire up the task manager, run cmd and then c:\windows\system32\restore\rstrui.exe
from the command prompt (edit the command if you didn't install windows in c:\windows).
See if system restore can rescue explorer for you.
If that doesn't work, run appwiz.cpl from the command prompt. This will fire
up the add/remove programs panel. Uninstall sp2 and your old explorer.exe should
work again.
If you want sp2, reinstall it. Then make a fresh copy of the sp2 version of explorer.exe
and store as backup. Make another copy to feed to resource hacker.
