[Sofaires]

ok, i build thisone, the problem im having is that every now and then i get random lockup and i have to shut it down by pressign the power for a few seconds, i think it is the heat but im not sure i use to live in michigan wich is pretty cold up there and i did have the problem but only like 3 times when the house was warm, it is not the ram i did change the ram to new ones thinking that was the problem but its not, i have the intel core 2 quad Q9400 with the original fan wich i think its the problem i just want a second opinion to see what you guys think... here is my set up:

Intel core2quad Q9400 @ 2.66ghz stock speed
Ocz dual channel kit 4gb Ram @ 1066
Evga 750i Motherboard
xfx nvidia 9800GTX+
rosewill PSU 550W
WD 320GB

everything its at stock speed, except for the ram wich the own box say that they support the 1066 and my motherboard support it too i use the volts like the box said 2.1v but like i said i change my old ram and did the same thing im right now in puerto rico wich the tempeture its almost always 80+ even in xmas what do you guys think could be?