Unzip and mount/extract the .iso.
Run Setup.exe and install. When asked to ("Activate VOCALOID"), select NO.
Now paste the "Patch.exe" file into the folder where you installed Vocaloid and run it.
Press "Patch" and voila!
[If the patch does not work, you must install update 1.1.2]

HOW TO UPGRADE TO 1.1.2

Unzip and run setup.exe.
Paste the "patch" file into the folder where you installed Vocaloid 1 and open it.
Patch!