Overheating problem

[cdietschrun]

I have an nForce 780i motherboard and a Q9450 CPU. I built it last July or August I believe, all new parts. I had an Arctic Cooler 7 CPU heatsink and MX-2 thermal paste. I have 2 120mm fans, one in the front and one in the back of the tower, with a Thermaltake case and an Antec 850W PSU. Everything worked fine at school for a year. I usually keep the computer on at all times, overnight, for days and days. No problems up until moveout day.

I moved my computer and self home from school yesterday and built a new desk for my computer. Turned it on, and after a while, it shut off completely, no warning. I knew in the back of my mind it was overheating but didn't see how it was possible. I moved it into a spot with more airflow and let it play for a few hours, and then try to use it and it shuts off. I watched the BIOS and the cpu temp is ~100C before shut off.

I bought new thermal paste today, wiped clean the cpu and applied the new paste, reinstalled the heatsink and turned it on and went to BIOS, watched the cpu temp go from 85C - 115C (!!) before shutting itself off.

What is going on? I know the CPU heatsink is installed correctly (at least I have to imagine it is), the thermal paste is on. The only thing I can't think of is the rear 120mm fan is orange and I don't see it moving on turn on, but all is plugged in.

Any advice/other things to look at/what to do?

 

[flyin15sec]

If you're sure that you have the HSF mounted correctly, make sure the fan is spinning. The only obvious thing that can cause that kind of heat is the HSF is not mounted properly, especially if you are using push pins.

 

[AKM880]

^ Agree with flying15sec, sometimes pushpins are hard to work with and they can also be a pain to mount

 

[jsc]

Contrary to intel's instructions, it's better to mount the CPU and HSF before you put the motherboard in the case. It's much easier to check for proper installation. You may need to pull out the motherboard to look at the back of the it to check for proper installation.

 

[Conumdrum]

jsc is right. I have found that the ONLY way to make sure is to have the mobo out so you can inspect the pins under the mobo. Lotta work, but sometimes it's less hassle just to go all out the first time.

Moving a PC with pins can easily pop a pin loose.

 

[cdietschrun]

I reinstalled/checked the pins on the fan this morning. Theyre about as in as I can make them. The BIOS is sitting with it now and the CPU temp is hovering at 79C which I don't like. The BIOS shows that my 2 chassis fans are at 0 RPM and I can see they are not moving at all.

Why are the 120mm fans not moving???