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I am hoping someone here can help me. I turned on my camera yesterday for the first time in about two weeks, and suddenly my LCD screen is showing bright green, along with all the pictures I take in any of the manual settings.
Now, if I switch me camera to the Auto Scene Intelligent settings, everything looks normal.
I have attached a picture to show what it looks like. 
One of the symbols shown in your photo for being in manual mode is showing that you are on a custom white balance. If you read your manual on how to change white balance or push the button with WB beside it, it should change the white balance and correct your screen.
Here is a tutorial from canon for the T3i (Canon 600D).
Also here is a for dummies how to set a custom white balance.
