- Create a temporary folder on your secondary NTFS partition (D:\ henceforth) labeled VISTA_TMP
- Extract Vista ISO image (e.g. with WinRAR) into temporary directory.
- Delete DRIVERS\, DOCS\, SUPPORT\ folders.
- Delete SOURCES\INSTALL.WIM image.
- Extract the boot sector from original ISO image and save in temporary location (e.g. Desktop)
- Create an ISO with the contents of the temporary folder and import the boot sector. The title of this ISO is irrelevant.
- Burn the ISO image to CD-R/CD-RW media.
- Empty but do not delete the temporary folder.
- Create a SOURCES\ folder inside the temporary folder.
- Re-extract INSTALL.WIM and BOOT.WIM into newly created SOURCES\ folder.
- Boot machine off of newly created Vista Preinstallation Environment CD, holding the CTRL key once the old Longhorn logo appears.
- Within' the command prompt, execute: xcopy X:\ D:\VISTA_TMP. NOTE: X:\ in the command above is not to be changed, it's the temporary RAM disk!
- After the copy process finishes, execute: D:\VISTA_TMP\SETUP.EXE
- Continue the setup process as if you had booted from DVD media. Enjoy!