First of all, make sure your Xbox is getting the correct amount of power. If the amount of power supplied to it is less than it needs, it will overheat trying to compensate for the lack of power. (google for help on that)
Also make sure that your Xbox is in an open area, and not surrounded by heat sources. Putting it on an elevated platform can also help with this.
Finally, it could be an issue with your internal cooling system, in which case you will need it repaired.
Last edited by Thorn; Aug 3, 2011 at 08:50 AM.