Thanks...

It was on for about 3 hours.
That day it couldn't have been more than 72-74 degrees F.
It did it with the mod removed as well.
Hmmm. Am I forgetting anything?

Just to get everything covered.
V 1.4-1.5 (according to xbox-scene's ID scheme)
X2.3b Lite +
120GB Maxtor
Phillips DVD
x2 4983(?)

Used heavily for the last month with lengthy play times.