I power my console ON & it's normal colors. I then put a game in & 3 min later all the colors have black spots & purple,green,red everywhere. I go back to Dashboard & it has it there as well.

I have 2 sets of cords & check them both but that didn't work. It does the same thing after I put any game in after 3 min.

I already sent them my Xbox 360 befor cause it had No Picture with sound(4 months ago). It took 6 weeks to get it back.

Plz don't tell me that I have to send it in again?

Sounds almost like a bad video card. Have you checked the Xbox Support page? You may very well be sending that puppy right back in.

The Dashboard is not as graphically intense as a game, but once the problem kicks in it won't go away till its restarted. It's usually cause by video overheating on computers, so I'm just kind of guessing.