Hi's Game of Mind

Hey guys! I’ve been bored a little bit, and I feel the clawing need to test the community’s intelligence at solving problems. I got my hands on a few codes, all for 1k GP. It may not be a lot to you, but it may be a lot to some people.

Bruce has done this before, so if you remember, it’s really hard, and it’s more of something to gloat about. My clues will be no easier.

Well, on to the games!

1. GREEW
Congratulations to unknown for redeeming
Hint: take a colour, and replace one of the letters on it
Hint 2: Second hint.
Hint 3: It's the last letter that you have to change with

2. CLUB4
Congratulations to NaTTerZ for redeeming
Hint: you join one of these + 16^1/2
Hint 2: 1/2 is a fraction
Hint 3: Glee _ _ _ _ + 16^1/2

I made a mistake on this one in the math, here's a free code to compensate: WXXKQ

3. NVYUD
Congratulations to newtonking for redeeming
Hint: En Vy Why You Dee?
Hint 2: Say hint 1 out loud
Hint 3: For salad's sake, didn't you learn basic letter sounds in school.

4. S2ADG
Congratulations to Henryblah for redeeming
Hint: I'm SAD, but I'm also 2G to be sad.
Hint 2: Mix the two certain words.
Hint 3: The order is LETTER NUMBER LETTER LETTER LETTER

Remember to post when you've gotten the code, so I can give you recognition!

EDIT:
http://crossfire.z8games.com/redeem2.aspx

Redeem it here, don't guess on the thread unless you know the answer.