Let's be sure what you're actually missing:
"Virus deleted explorer.exe"
"I want to replace it with a new explore.exe so I can easily delete/quarantine the virus that did this."
explorer.exe is the Windows Program Manager or Windows Explorer. Right click on Start> Explore.
explore.exe is added to the system as a result of the GRAYBIRD.G virus.
Sounds like Explorer.exe is not starting properly, or Explorer.exe is not
selected as the system 'shell'. Can you manually start Explorer.exe (This is
WINDOWS EXPLORER - NOT INTERNET EXPLORER) from the Task Manager ?
Explain what you mean by using this to delete/quarantine the virus.