The loader for a convenient wubi-installation of Ubuntu, can be easily re-added to the Windows Vista/Windows 7 bootloader.

After you have transferred all Ubuntu related files to the new root drive (files: wubildr and wubildr.mbr and the ubuntu directory), open a new Console as Administrator and run the following commands to add Ubuntu to the boot menu:

• bcdedit /create /d "Ubuntu" /application bootsector This will return an identifier in the form of a GUID - in the following commands, replace {ID} by that identifier!
• bcdedit /set {ID} device partition=C:
• bcdedit /set {ID} path \wubildr.mbr
• bcdedit /displayorder {ID} /addlast

Done. Upon the next boot, a new entry Ubuntu should appear in your boot menu.