every time i turn my mac on, on the logon screen, instead of my profile picture, it appears a question mark, and when i hit the hint button, it says that the user graphic resources seems to be invalid. and i am the only user of my computer and i have alredy turned off the guest user, but i still remains there, as an "only safari enabled guest account". what do i do to fix the profile picture and the graphic resources problem? and how do i disable the "only safari enabled guest account"?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic