PC powers up CPU fan high but no boot

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Shafra

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Actually, I should say occasionally, like 1 out of 50 tries it MAY boot. Not sure what's up. This is an HP PC a1630n. Before I spend tons of time on this, what could this be? I'm thinking maybe a power supply??

The PC powers on and the CPU fan revs up on the highest speed and nothing boots. On that odd chance it does boot the CPU fan runs high for the typical 2 seconds, slows to normal, and then the hard disk starts to grind and the system powers up.

Any thoughts appreciated! Ask if you need more info.
 
Could be that the fan and heatsink are filled with dust. Could be that the fan is dying and it is over working itself cause it cant keep up with the colling any other way.
 
I replaced the heat sink and applied new thermal compound. I'm guessing the motherboard or CPU died. The PC also automatically turns on when the power cord is attached, even if the front header wires are disconnected. I have 2 ram sticks, removed and swapped them around, disconnected everything except for the necessities. Tried a new power supply, same thing. Only other thing is the video, this unit has onboard video. But since the PC turns on just from plugging it in and I have no beeps at all, still seems to point towards CPU or motherboard.

Any other ideas?
 
Does it even POST? If not i would wager to guess mobo.
 
No post. No beeps.

The odd thing is, out of the last 150 times I tried to boot the thing one time, just randomly it booted all the way into XP, but never again. I guess whatever was dying, died. Even reset the Cmos.

Hey all, wanted to update this thread to get some more feedback.

As I mentioned PC just powers on when you plug in the power cord. If I continually unplug and plug back in the PC eventually, sometimes after many tries it will post then boot. Temperatures are all fine, once into the OS all runs well, no shut downs.

What the heck could this be?? Would a CMOS battery going bad stop the post and cause me to have to restart the machine over and over again? Something on the motherboard going bad?

Also when I get a successful boot if I reboot/restart the system it will always 100% hang at boot. This problem is happening when the PC begins to start, any ideas?

Never seen this before...
 
A CMOS battery being dead could stop it from POST'ng cause well the CMOS stores the BIOS. So if the CMOS is dead then the BIOS cant load.

Can try to replace the battery and see what happens.
 
Replaced the CMOS battery and was excited the system booted 1st try, however after saving the new BIOS settings and rebooting it hung. I can still get it to boot if I constantly unplug and plug in the power cord, but this can't be a good sign.

I've really tried everything I can think of, this has to be some motherboard issue right?
 
If replacing the CMOS still doesnt net you any results i would see if there is a BIOS update out there first. If that still doesnt net any results i would then conclude that it would be the mobo.
 
I have the same issue - CPU fan and motherboard LED work, but no beeps, no video, no keyboard/mouse lights and nothing starting. CPU fan comes on with PSU connected to power but front power button has no effect. It's a new motherboard and CPU and a tested PSU. I'm suspecting the RAM which came from the last system that died and that this one is replacing. I'll try booting with no RAM installed (didn't know I could do that) and see if I can get anything. I had already disconnected all drives to eliminate them. My video is an ATI card in the AGP socket, so I'm not sure if I can trust it to give me startup screen display.
 
hey there, did you ever get this fixed? i found this thread via a google search because i was having the same issue. after doing all the same stuff you did too i finally decided to try a process or re-seat. I just removed the heat sink, unlocked the processor and pulled it out, inspected the contact pins (they all looked OK) reinstalled it all and it corrected the issue. it has been running all day not on the bench.
 
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