Replaced heatsink/fan, now computer won't respond at all

Hi - I’m posting by proxy for KrustyKlown, whose employer blocked access to the SDMB.

Here’s the situation:

I had a very loud CPU fan on my computer. It worked fine, but it was LOUD. I had to wear earplugs just to drown out the fan. So I decided to replace it, and the heatsink, finally got the replacement unit (that’s a whole 'nother story), took off the previous one, and strapped on the new one. These heatsinks are, I must say, incredibly difficult to attach. You really need to jam the little metal “belt” down there for it to click, and I’ll admit that I hit the motherboard a few times with my implement (I used
a flat head screwdriver at times and a leatherman at times). Anyway, I finally got it on, turned the computer back on, and nothing. My monitor is flashing yellow and all I hear is two sounds from the computer (hard to describe), when I could swear that I normally hear three. Also, absolutely no BIOS at all. I tried everything I know, including disconnecting all the cards but the video card, and disconnecting everything but the hard drive, and still nothing.

So the question is: What the hell did I do? Did I kill the CPU, which seems possible because I was attempting to put a very heavy heatsink/fan on top? Did I somehow short out the BIOS chip, or otherwise kill the motherboard? Did the video card conk out for no good reason? What would cause these sorts of symptoms? Could a non-working CPU cause the BIOS not to even show up, or the monitor not to “take” to the motherboard?

If you have any ideas or suggestions, my eyes and ears are WIDE open. All help is very appreciated.


Installing heatsinks can be a bitch. The newer models that screw down are much easier to deal with than the older style clip ones. Of course, your mobo needs to have holes that accomodate the screws.

It is hard to tell from here what’s gone wrong but my guess is one of a few things:

  1. Some mobos don’t want to start unless they see a fan attached. You’d have to check your mobo documentation to see if this is the case. Often the fan must be plugged into a particular header for the mobo to realize there is a fan present. Also along these lines some mobos want to monitor the RPM’s of the fan. Not all fans report this info to the mobo. If your mobo is picky about it you may need a new fan (not likely but you never know…check your manual for detail to be sure).

  2. Your CPU is inserted the wrong way. There is a corner of the CPU that looks like it’s been clipped off just a bit. This corner need to align to a specific corner of the socket. With the heatsink strapped on you may have gotten the CPU spun the wrong way (since you usually can’t see the chip under the heatsink). Make sure the CPU is inserted properly and locked down.

  3. You cracked your CPU. This is quite possible when installing heatsinks. Athlon chips now have little rubber footpads on the corners to help alleviate the chance of this because so many people were destroying CPU’s while installing heatsinks. If this is the case you are SOL and need to buy a new chip.

  4. You damaged your mobo. When I installed my heatsink I also used a flathead screwdriver to get the clip on. I was sweating majorly as I knew if the screwdriver slipped I’d punch a whole clean through the mobo (and it could have easily slipped). This one is a tough call to diagnose. If all else fails buy a new mobo and see if that works. You can always return it if that doesn’t turn out to be the issue.

Best of luck…

um… is this a joke? you HIT the motherboard? sounds risky for a start. Its unlikely, but you may have damaged the chip or motherboard from static electricity, as I don’t know whether you took precautions or not. If you build up a static charge on your body (not necessarily even enough to get a shock) you can damage some sensitive motherboard components, or even the chip. If you have synthetic carpets or something, and you walked on them before working on the computer, its possible this happened, but its more likely you did physical damage to the chip/motherboard itself.
It sounds like the computer is seriously damaged/something disconnected because even if your CPU was overheating it should work for about ten seconds before it crashes. I assume that you checked, and the fan was working when you turn on. I reccomend you take the heatsink and fan off again and see if you can see any visible damage to the CPU. Do this for the motherboard as well, particularily the back, as you may have broken one of the copper rails on the back.
Can’t help you much more than that, I’m afraid, without more info.

Well, those beeps the computer makes are the way your computer alerts you to a specific problem. I just can’t translate them.

You could try reseating your video card. Or the RAM.

See if you can get it to boot with video card, RAM, and HD.

Does the system give off any beeps?

Also, touch your hand to an unpainted metal surface like the side of the case or the power source. Then take your other hand and gently touch all around the motherboard. This will clear built up static - it may be too late, if it is damaged - but maybe not.

When we were building my friend’s computer, it failed to function until I checked for static… and I ran my hand around in that manner, got a big shock - and then, after clearing it, it worked fine.

Also, did you use any thermal interface material, such as Arctic Silver 3 or Arctic Alumina? Or did it have a thermal pad on it? Did you smell smoke? If so, you may have fried the chip from improper core contact (or if the HSF is sitting on the lip of the socket and not touching the core.)

However, if you didn’t smell anything, or hear a pop…it likely is either a crushed core, or even more likely, the fan isn’t plugged in right, like a-mole said.

Turn on your computer with the case open. Check see if all the fans and coolers got power.

Is your keyboard connected properly?

Per the other suggestions and based on your description of your ummm… “robust” service procedures you most likely have

1: Cracked the CPU

2: Broken a trace on the MB

3: Not plugged the CPU fan in properly

4: Jostled something loose like the seating of a video card, a memory chip or a jumper/switch
Only 3 and 4 are solvable without buying new equipment.

Also make sure you connected the power switch lead to the board. ATX cases usually only start if that is
connected. ATX cases have two power switches, mine do anyway.

You guys are going to kill me. Hell, I’m gonna kill myself.

After purchasing a new CPU, and testing it, I got the same result. So I bought a new motherboard (driving about 1 1/2 to CDW and back to get it), same thing. So finally, I bought a new video card at Micro Center. Same thing. I tried the monitor on the back of a laptop I had available, and it worked just fine. So I basically decided that the computer gods had frowned on me, and nothing I did would ever work again. Then, I jiggled the monitor cable a bit behind the video card on my normal computer, and the signal finally transmitted. So I went back to my old CPU and old video card. Still worked. I kept the new motherboard (because I like it, and because I don’t want to go back to Aurora), but I bet the old one would workjust fine too. So after all is said and done, it looks like all I had to do was twist the monitor cable a bit. Sigh. Worst part is I tried it on the laptop, and it worked, but put it back on the desktop, and it still didn’t at first. Oh well.

On the bright side, my new fan and heat sink are just what I wanted. Much, much quieter.

Thanks for all your suggestions.


Well, you could look at the monitor connector & see how it looks.

I don’t think you tried my tests.