How do I get the Wubi installer to use a pre-downloaded ISO?

Note: wubi.exe will say "downloading files" for a short time even if it is using the pre-downloaded ISO. Please follow the steps below and try again.

Quick links to wubi.exe and appropriate ISOs:

• 10.04.4 Lucid LTS: wubi.exe, 32-bit ISO, 64-bit ISO
• 11.10 Oneiric: wubi.exe, 32-bit ISO, 64-bit ISO
• 12.04 Precise LTS: wubi.exe, 32-bit ISO, 64-bit ISO

Requirements to use an existing ISO:

In general, here are the requirements to use a pre-downloaded ISO with Wubi along with my recommendations for a successful install:

• You must download the desktop CD version of the ISO and place it in the same directory/folder as wubi.exe before running wubi.exe
  • Get both wubi.exe and the ISO from the same server folder, e.g. http://releases.ubuntu.com/lucid/
  • I highly recommend creating a new folder with but two files in it: wubi.exe and the ISO
  • The ISO can be 32-bit (i386) or 64-bit (amd64); Wubi will happily install whichever it finds in its folder.
• Alternate/server ISOs are not supported
• DVD ISOs are not supported except for Edubuntu

Illustration of the misleading "downloading/retrieving" issue: