Pc does not post

Something happened to my pc after took it open for cleaning. I did some dusting with dry cloth, and removed the cpu air cooler to blown away the dirts stuck between its fins. When i put everything back and powering on, the pc will either:

a) its cooler, PSU and system fans will run 1-2 seconds before immediately power off automatically. No error beeps at all.

b) the pc is powering up (PSU and system fans will run continuously), but no POST at all, neither the error beeps.

So far, i tested with another PSU and motherboard but the problem remains. I tried to take everything out and put together again and still no luck.

What else could be the problem? Is it possible the processor gone kaput (i only detached the CPU cooler for cleaning) or i didn't properly re-applied the cooling paste on CPU and so the system prevented the powering up?

Are all cables connected correctly? An old HDD cable in the wrong direction can cause such trouble. Or maybe a RAM module got loose.

Do you have an old mainboard + CPU plus RAM plus a crappy graphics card? Maybe you can test some of your equipment with it.

Originally Posted by Gorath
Are all cables connected correctly? An old HDD cable in the wrong direction can cause such trouble. Or maybe a RAM module got loose.

Do you have an old mainboard + CPU plus RAM plus a crappy graphics card? Maybe you can test some of your equipment with it.

Yes, try it without any drives plugged in just to see if it posts. And if you have another CPU and mobo, that would be a great help to rule out everything else.

How did you remove the CPU cooler? There should be a very thin layer of a thermal compound in between the surface of the CPU and the contact of the cooler, and if that layer gets disturbed, the CPU can overheat very rapidly and shut itself down right away.

With having no post screen and no error beeps i said ah! its the bios memory (battery) but to have the same problem with another motherboard would cancel this out.

Ouch, bummer. Reminds me of the time me and a friend had the idea of washing the engine of my old Camaro. Never ran the same after that.

Sounds to me like the processor is getting very hot, very quickly, and shutting down quickly. Or a memory issue, did your RAM somehow get disturbed in the process, everything seated ok?

You probably connected the power supply for cpu-fan to wrong outlet on the mainboard. Verify that it's correctly connected to the dedicated cpu-fan power supply (3-pins, there's usually 2-3 similar power outlets on the mainboard).

Also check:
- Main powercable to mainboard (20-24 pins)
- Additional powercable to mainboard (4 pins)
- Powercable to graphicscard

I recheck again the PC by the following conditions:

1 - detached graphic card from m/b = result as in a) in my first post.

2 - detached sound card from m/b = as in a)

3 - disconnected front panel USB & multi-reader connections to m/b = as in a)

4 - disconnected all hard disk & DVD writter connections to m/b = as in a)

5 - re-attach my RAM = as in a)

6 - tried with another PSU without hardwares in 1 - 4 above = now the PSU and cpu fans

ran continuosly as in b) in my first post.

7 - tried on a new m/b with basic connections (CPU fan, with or without grahics card and

RAM) = result as in b) in my first post.

Look like it is the processor. the processor and the area directly under it didn't feel warm (at all) after i tested for 10 minutes. I didn't detach it during the clean up, may be i used too much force when pushing down the air cooler's hook into m/b.

Remove and replace the bios battery on the motherboard. Worth a try.

Definitely try the bios battery. It's probably a CR2032 and they're real cheap. If you have another pc, a diabetes tester, or some types of watches, you may already have a spare battery that'll allow you to test. I also like the thermal compound idea. If you're missing that thin layer of stuff, (let's say it got dried out and then the air from blowing it out removed it completely), then your cpu will overheat in seconds.

I replaced the Bios battery and re-applied generous amount of thermal paste - still no go. The pc is powering up (PSU and system fans will run continuously), but no POST or any error beeps.

Originally Posted by Remus
The pc is powering up (PSU and system fans will run continuously), but no POST or any error beeps.

So it's running with no error signals, but you're just not getting anything on your monitor? At least that eliminates the possibiility that your CPU, vid card, or memory isn't seated correctly.

Is your monitor powering on normally with the rest of your system?

Try another RAM dimm,or at least change it's slot.

Originally Posted by JDR13
So it's running with no error signals, but you're just not getting anything on your monitor? At least that eliminates the possibiility that your CPU, vid card, or memory isn't seated correctly.

Is your monitor powering on normally with the rest of your system?

I should say no error beeps, as well as the single beep under normal circumstance when a pc successfully post after pressing the power button. My monitor is on together with PSU and system fans but displaying "no signal" message, and then the monitor goes into sleep mode.

Originally Posted by Kostaz
Try another RAM dimm,or at least change it's slot.

Usually there's multiple beeps if something wrong with RAM, and i moved two of the four sticks onto new motherboard with same result.

The CPU could be kaputt. The PC will boot with fans running on max if the cpu fails. Try removing the cpu and check for broken pins (if it has) etc.

It sounds like the CPU is the problem but try with 1 dimm on,just for the sake of it.

Originally Posted by hishadow
The CPU could be kaputt. The PC will boot with fans running on max if the cpu fails. Try removing the cpu and check for broken pins (if it has) etc.

It is the E6750, no pins. I tried it without fan attached, nothing in term of result

PS - i tested with one DIMM, without cpu fan and graphics card attached, still no nothing.

PSS - i would take out the processor and send to computer shop to verify it's dead or not. Damn!

Originally Posted by JDR13
At least that eliminates the possibiility that your CPU, vid card, or memory isn't seated correctly.

Actually, the latest computer I built didn't boot properly at first with no beep codes, despite the only error being that I had managed to put the memory sticks into slots 2&4 instead of 1&3. Or 3&4 instead of 1&2, I don't remember exactly how they numbered them now.

Yep, memory config can be critical (or no boot and no beeps)

If the four sticks of ram have previously had two added to the original two, then the pairs must be maintained to cancel out any disimilarity.

Usually slot one and two is bank O, slot three and four bank 1, slot five and six bank 3 and slot seven and eight bank 4….but it is the "pairs" of banks that must keep "ram pair" priority.

eg:- Even though the exact same slots are populated as prior to cleaning, swapping the pairs over could lead to non function.

Suggest to swap stick one with stick two of pair 'A' and/or possibly follow by doing the same for pair 'B'

can you follow that? - solved a problem on an Abit motherboard using same method.

Worth a try…?

im curious to see how this one turns out, pc mysteries are pretty interesting.

I just fixed a friend's pc who's dvd was running very slowly and was assumed it was going out. In reality, the IDE channel flipped down into PIO mode. Tell ya, learned a little something interesting from that little adventure…

DMA flips to PIO mode