How can I enter Unicode characters (e.g. ♥♦♣♠) when logging into Windows?
Solution 1:
On Windows 8 logon screen you just have to be really fast to type ♥ in password field. Don't hold the Alt for too long. I don't know how fast are your fingers, but you can probably forget about codes longer than 3 characters.
Besides those characters are obviously not supported I would not advice to use them, because they won't add as much entropy as you may expect.