this is after dust cleaning cpu fan ,Mboard

August 1, 2011 at 21:36:44
Specs: Windows XP, 2GB
pc not booting shuts down while loading OS.it was working Pentium4(Intel) desktop PC with windows 7 OS
I opened CPU fan dust cleaned and fitted it back

See More: this is after dust cleaning cpu fan ,Mboard

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#1
August 1, 2011 at 21:53:41
"it was working .."

Was it working immediately before you cleaned inside the case ?

Did you use a vacuum cleaner ? They produce a tremendous amount of static electricity when running and can discharge that to anything inside the computer case and damage it if anything connected to the vacuum cleaner touches the mboard or the components on it, or the drives, or the power supply.

Otherwise.......

The CPU fan 3 or 4 wire wiring connector must be connected to the CPU fan header on the mboard, and the CPU fan must spin when you boot the computer - the mboard will probably shut off in a very short time due to bios settings or bios code defaults if no rpm is detected from that header by the mboard's bios.


To make sure you haven't knocked something loose, remove the AC power to the case, check all the wiring connections inside the case and make sure they're all the way down on their pins or all the way in to their sockets, and make sure the ram, and any cards you have in mboard slots, are all the way down in their slots.


It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittent, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.

Try another data cable if in doubt.


Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place.
(There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged)

The same thing applies for the SATA power connection.


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#2
August 1, 2011 at 22:25:33
Thank you for your guiding tips Sir/Ms. Now I am able to boot and it shuts down abruptly while loading windows 7 OS.During this phase I have checked and found CPU and power supply fans are working normal.

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#3
August 1, 2011 at 22:41:19
I'm male. No need for Sir.

Was it working immediately before you cleaned inside the case ?

Did you use a vacuum cleaner ?


The mboard shutting off and staying off rather than restarting can only be caused by a hardware problem.

Make sure the CPU fan is connected to the CPU fan header, NOT another fan header.

If you used a vacuum you may have damaged something, perhaps the power supply. Try another power supply if you can.

If the cpu fan can be mounted either way, you must be able to see the whole fan blade on the top when it's installed on the CPU's heat sink, no non moving center portion or fan strut in the way. If that's backwards the CPU will not be properly cooled. However it would take a while, not a short time, for the CPU to get hot enough to cause problems.

I'm assuming you DID NOT remove the cpu heat sink from the CPU when you were cleaning.

I'm off to bed now.


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#4
August 2, 2011 at 05:43:03
"I opened CPU fan dust cleaned and fitted it back"

Did you actually remove the heatsink/fan to clean it? If so, did you apply fresh thermal paste between the CPU & heatsink? If not, that's the problem. Old paste should NEVER be reused. New paste MUST be used & it MUST applied correctly.


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#5
August 2, 2011 at 06:25:25
Ok i will try P.S , all connector wiring and new thermal paste and contact you ; thank you for your guidance

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#6
August 2, 2011 at 08:39:26
If you DID NOT unclamp the heat sink , don't do it now !
If you DID unclamp the heat sink but it's bond to cpu has not been loosened such that the heat sink can move, don't unclamp it now !
Thermal compound or thermal grease or a thermal pad does not spontaneously stop working !
.......

Attempting to remove the heat sink from the cpu when you don't need to can cause you problems you didn't have before !

DO NOT attempt to remove the heat sink if it will not break loose from the cpu when you have unclamped the heat sink and you press straight down on the heat sink and try twisting it sideways on the cpu. If it's stuck to the cpu the thermal compound will still work fine !.

In some cases thermal compound has hardened and it's as if the heat sink were crazy glued to the CPU. In that case you can't remove the heat sink separately, and on newer mboards you usually can't release the lever on the cpu socket to unclamp the cpu because you can't remove the heat sink and it's in the way.

If you can't move the cpu socket lever that unclamps the cpu when the heat sink is in the way, the only way you can remove the stuck together heat sink / cpu assembly is by pulling straight up on the assembly which can easily damage the pins on the cpu or damage the closed cpu socket. .
If you DO remove the assembly that way, if you can't pry the heat sink off the cpu, and if you can't move the cpu socket lever that unclamps or clamps the cpu in the socket when the heat sink is in the way, you can't re-install the assembly properly !
.....

I have removed a few older stuck together heat sink / cpu assemblies, on older mboards when I was able to move the cpu socket lever to release the cpu because the heat sink was NOT in the way, but I found it was impossible to pry the cpu from the heat sink (e.g. I broke several heavy duty single edge scraper / razor blades attempting to do so), at least not without risking damaging the cpu, so I left it as it was,. and those cpu ./ heat sink assemblies still cooled / cool the cpu fine.
.....

If you DID remove the heat sink from the cpu, you may have not installed the heat sink so that it is sitting flat on top of the cpu.
......

Unless you tried booting the computer many times one time after the other....

Re-using thermal compound or thermal grease will NOT cause the problem you're having with the mboard shutting off in such a short time. Even having nothing at all between the heat sink and the cpu will not cause the problem you're having with the mboard shutting off in such a short time.
The cpu would have to be running long enough for it to overheat - if the heat sink is sitting flat on the cpu that will take longer than you're experiencing for the mboard to shut off.


Thermal grease - pure silicon grease with no additives - whitish, translucent, nearly clear when in a thin layer - can be re-used, if it's clean - it never hardens. Thermal pads should not be re-used - the remains should be scraped off and be replaced with thermal compound or thermal grease or a new thermal pad . I don't recommend re-using thermal compound because even if hasn't hardened it may harden in the future and be as if it's crazy glued to the cpu.

I never use thermal compound anymore - thermal grease has never caused me any problems - it never hardens.
I have always been able to break loose the bond of thermal grease or a thermal pad when I unclamped the heat sink and pressed straight down on the heat sink and twisted it sideways on the cpu, but I don't recommend using thermal pads.


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