Originally Posted by David Lindon
Are you using the stock heat sink? Is it fitted correctly?
Let me take what David asked a bit farther.
If you didn't use thermal paste between the cpu chip and the heatsink then it's gonna get heap plenty hot. Got to have the paste to pass on the heat from the chip to the heatsink. Too much and it acts like a insulator blanket. Again getting hot because the heat is trapped under the paste. A dot about the size of a grain of rice does nicely. Smear it around the central portion of the cpu chip completely covering the center square. Plug in the chip and set the heatsink with the fan attached and lock it down. I always let the rig sit for about 10 mins or so before I fire it up. Just an old habit but seems to let the paste get settled out before applying the juice.
Intel's stock heatsink and fan setup is rated as one of the best for Intel cpus and that's not just me talking crap. It's a fact you can look up.
As for cooling the case, the fans in the front and side blow into the case and the ones in the back and the top blow out.
155F is not going to kill the chip but it will cause it to throttle back or shut down to let the cpu chip cool off. The problem you have is very simple to fix. Take your time and check the things I have suggested.
If you need more help just come back here and ask. We'll be here...