[FlyACL]

Sometimes it is hard to narrow down the cause. It could be heat, it could also be the disk or even an Internet connection problem. Sometimes when my network has a lot going on (ie computer being used, wi-fi laptop on, etc) while I am gaming online it will slow down and sometimes freezes. I personally think the whole "The disk is dirty" message is just what MS decided to have come up when the system can't figure out what is wrong. Something like "Something is wrong... I don't know what... Must be the disk... ".

I would give it some time and see how it goes before you do anything. Make sure it is not the disk (see if it happens with other games). See if it only happens when you are online. Then see about a fan or cooler.

But, that is just my two cents... Good luck~