When i press Singleplayer it says:

Minecraft.net returned incomplete server details.
Missing:User
Do you wish to retry or quit?

And when i click sign in it says:

Unable to authenticate Your username/password may be incorrect or there are not servers to validate you login.

Im using my Minecraft username and password. Thats what youre
supposed to do, right? if so, please help me with whatever else might be
wrong.