I can play movies all day but when I go to play any games it overheats I don't know what is wrong with it. I have opened in up and cleaned it out. It's really upsetting that I can't play my games.
2 Answers
Playing a game is way more demanding than playing a movie so of course the Xbox generates way more heat then.
However playing a game should not cause it to overheat, you say you've already cleaned it so it's probably not dust in the system. Try putting the system in a place where more air can flow around it. Also keep it far away from the power brick, first generation xboxes adapters get quite hot.
Open it up, remove dust, check if the cooler is still decently mounted on the motherboard. Over time the motherboard might bend, severing the connection with the aluminium cooling block. Maybe apply some new cooling paste. You could also get one of those cooler strips to mount on the backside.