Overheating, but wont work with new cpu fan??

  Varlo 18:59 01 May 2012

Hi Guys,

My pc (approx 2 1/2 years old)started overheating a couple weeks ago, shutting down, fan whirring up and restarting, also showing a cpu temp of about 60deg C. I took the case off and gave fans, case vents etc a going over with compressed air which seemed to fix the problem. A couple nights ago same thing happened and on restarting it couldnt get into windows without it shutting down on me. It will however work fine with the case off so i can only assume its an overheat problem. I picked up a new cpu fan and fitted it today, (no problems like a glove), but on turning my computer on it fired up first time ok for a couple minutes then froze completly. Trying to restart it the only life it showed was the fans going. After a bit of head scratching and beer drinking, I refitted the old cpu fan and it is back up and running again (with side case off),but on start up got a message saying overclocking failed?? Any thoughts? i've changed basic components before and never had anything like this happen. Cpu is Intel Core 2 Q9550 quad 2.83ghz, and if it matter 4gb ddr2 ram, Radeon 4800 series graphics card, 1TB hard drive.

Any advice appreciated

  johndrew 19:31 01 May 2012

Could be you don't have a good contact (thermal paste?) between CPU and heatsink.

  Terry Brown 19:33 01 May 2012

If, as it sounds like , you have overclocked the machine, there is a good chance that the new fan is not powerful enough to keep the CPU cool, and so it has reverted to standard operating speed, but cannot boot because the bios is set wrong.

I have never tried manual overclocking, so I don't know what you need to do to reset it, however I would suggest you clear the BIOS- either reverse the switch- wait a minute or so and return to normal or remove battery and leave overnight before replacing the battery.

When you cleaned the case fans etc; did you make sure the Heat sink for the CPU was clear, as that is a common cause of overheating.


  KRONOS the First 19:33 01 May 2012

When you say changed the fan,what exactly do you mean? Are you the stock cooler that came with the CPU or are you using an aftermarket one? Did you replace the thermal paste? Is the fan connected to the correct header on the motherboard ?

As for the message on start up,do not worry about that. I believe that it asks you to press F1 to enter setup, do so then when th bios screen appears press F10 then OK. See if PC starts OK. Post back.

  KRONOS the First 19:37 01 May 2012

Why the hell can we not have an edit button?

Using should follow are you* in the above.

  Varlo 19:53 01 May 2012

Thanks Terry & John for your time,

No i have never overclocked my machine, tbh my knowledge is limited and i wouldnt want to attempt it. I did do the f1 and f10 and am on my pc now, again with case off and windows open to be on the safe side. It was the stock fan i was replacing and an aftermarket one that didnt want to make my pc work at all. I did clean paste of the cpu with isopropyl and the replacement had some pre applied. I thought i cleaned the heattsink properly a couple weeks ago but doing my change today it did look a bit clogged with fluff, attacked with a flux brush this time around as well as air. (it was dark first time around). Perhaps that was the main problem but i still dont understand why my new fan wouldnt work as my old one sounds weedy and doesn't seem to be pushing much air around. Perhaps put the case back on and see how i go? or maybe run a full scan to put the cpu under a bit of pressure and see how if ti completes?

  Varlo 19:59 01 May 2012

Agree add edit button,

EDIT- Thnks to Chronus as well


  Fruit Bat /\0/\ 20:06 01 May 2012

Is it possible you connected the fan wrong way round so it ran backwards?

  Varlo 20:29 01 May 2012

"Is it possible you connected the fan wrong way round so it ran backwards?"

Very very good point, didnt think to check. Will have another go in daylight.

Will report back even if im hanging my head in shame.

  KRONOS the First 02:25 02 May 2012

Very tricky to instal the fan connector the wrong way round,as one side has two guides which correspond to a plastic part on the header. Not impossible but as I say tricky. I think the problem lies in how you are either seating the cooler or connecting it. I do not understand why a aftermarket cooler stopped your PC except that it was incorrectly fitted and was not doing its job.

  robin_x 09:38 02 May 2012

Connector might be alright but fan might be facing the wrong way.

Check for fluff in hidden nooks and crannies in the air path/'ducting'. Especially when directed through thin fins. See if you can see through them if possible.

Double check the 'pre-applied' paste is OK and all parts surfaces mate properly on it.

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