Launching Minecraft requires administrator privileges?

Downloaded MC 1.6.4 yesterday to a Windows 7 machine.
Where are Instructions HOW to start the game?

It seems to be possible to start it with the downloaded Minecraft.exe
BUT1: that exe is only the "Downloaded" folder subject to be removed and
BUT2: there requires administrator privileges when it download and launches.

The user, a child, has privileges to his own folders, including the .minecraft folder.
Should the game start from some exe or jar in the .minecraft folder?

Tried launching the jars in the .minecraft folder WITHOUT succeeding. Tried with both Java JRE 1.6 and 1.7

Trial1 and its error:
C:\Users\Aki\AppData\Roaming\.minecraft>java -jar launcher.jar
no main manifest attribute, in launcher.jar

Trial2 and its error:
C:\Users\Aki\AppData\Roaming\.minecraft\versions\1.6.4>java -jar 1.6.4.jar
Error: Could not find or load main class net.minecraft.client.Main