Method
Start - Search - Administrative Tools - Local Security Policy.
Local Policies(left) - Security options(right).
For a title
In the details panel double click Interactive logon: Message title for users attempting to log on.
And for a small text entry below the title
In the details panel double click Interactive logon: Message text for users attempting to log on.
Type in the message you want to appear and click apply.
Restart your pc and see the changes.
Software used
Windows Movie Maker - for editting
Music by
Black eyed peas - meet me halfway
Made by Superman|SA
END