Windows won't load; computer shuts itself down

[Paul]

This afternoon, my five-year-old desktop started shutting itself down
(immediately after being turned on) before the Windows screen is visible. I
usually see the BIOS screen with the Dell logo; once I have gotten the
options to start Windows normally, other times it will shut down before I
can even see this screen. I checked the monitor and it is plugged in; we
have added no new hardware at all. Any suggestions?

 

[SC Tom]

This afternoon, my five-year-old desktop started shutting itself down
(immediately after being turned on) before the Windows screen is visible.
I usually see the BIOS screen with the Dell logo; once I have gotten the
options to start Windows normally, other times it will shut down before I
can even see this screen. I checked the monitor and it is plugged in; we
have added no new hardware at all. Any suggestions?

My guess would be power supply. Either that or your CPU fan has quit/been
jammed with dust. Open it up and take a look and see if there's a bunch of
dust bunnies, cat hair, etc. in the heat sink and fans.

SC Tom

 

[Paul]

Excellent diagnosis. I took off the case and vacuumed. Lots of cobwebs.
After replacing the shell, I turned it on again and noticed that I didn't
hear the fan. I would assume then that it needs replacing.

I've also had bad caps with this unit, and I've been telling myself no more
hardware upgrades on this unit--I'll just buy a new desktop when it comes
time. But I'm thinking that a fan is gonna be a lot cheaper and it would buy
me a few more years....

 

[SC Tom]

Quite often, you can clean the spindle on the fan and oil it and it'll work
for a long time. Take the sticker off the back side of it and pop the little
rubber plug out. Reach in there with a small knife point or old jeweler's
screwdriver and pop the round keeper off the shaft. Pull the fan out, being
careful of the order of the spacers. Clean the dust and dirt out from the
inside of the fan, put it back together except for the rubber plug, and
squirt 4 or 5 drops of 3-in-1 oil in around the shaft (you don't need much).
Put the plug back in, use a little alcohol and clean the area around the
plug, and put the sticker back on to hold the plug in. If it doesn't stick,
you can use a piece of masking tape instead.
Works like a champ!

SC Tom

 

[Randem]

You said you have bad caps with that unit? Would it be a GX270 or GX280? If
so you can replace those caps with a cap kit from "The Cap King" if you are
handy with a solder iron... If not then a replacemen system board is about
$90.00.

--
Randem Systems
Your Installation Specialist
The Top Inno Setup Script Generator
http://www.randem.com/innoscript.html
Disk Read Error Press Ctl+Alt+Del to Restart
http://www.randem.com/discus/messages/9402/9406.html?1236319938

 

[Paul]

No its a Dell Dimension 2350. Thanks for the suggestion, but 90 is a lot
more than I'd be willing to put into that, when I can get brand new units
for 350. I can handle a 15-dollar fan, but a motherboard is another issue.

 

[Paul]

I vacuumed out the fan, and got it running again, but it still shuts
down--it just lasts a bit longer before shutting down (now, I can actually
see my desktop for a few seconds before the automatic shutdown).

 

[Paul]

I vacuumed out the fan, and got it running again, but it still shuts
down--it just lasts a bit longer before shutting down (now, I can
actually see my desktop for a few seconds before the automatic shutdown).

Has a clip broken on the heatsink ? It almost sounds
like the thing might not be pressed down tight to
the processor.

Does the fan speed seem "normal" ?

Paul

 

[Paul]

Yes I think I saw two--but only one was still working. I"ll give that a
shot.

 

[Paul]

Well I re-inserted the fan, and it went a lot longer before shutting
down--about 2-3 minutes after the desktop first was visible. I'll go ahead
and tinker with the fan some more--I heard a click, but I'm not sure it is
snapped shut. Thanks for the suggestion.

 

[Paul]

Actually I didn't unplug the cable from the motherboard. As far as the fan
itself, the plastic case that it is in, is firmly attached to the
motherboard--I had to jimmy it hard to detach it, and then I put it back in,
so unless I've not been troubleshooting this right, I don't think that the
problem here is that the fan isn't properly connected.

 

[Paul]

Actually I didn't unplug the cable from the motherboard. As far as the
fan itself, the plastic case that it is in, is firmly attached to the
motherboard--I had to jimmy it hard to detach it, and then I put it back
in, so unless I've not been troubleshooting this right, I don't think
that the problem here is that the fan isn't properly connected.

I was thinking more along the lines of this.

http://support.dell.com/support/edocs/systems/dim2350/replac73.jpg

The heatsink fits into the retention bracket. The retention bracket
is made of plastic. The two metal things press down on either
end of the metal heatsink. The heatsink bottom, has thermal
interface material (thermal pad or paste material), to aid in
heat transfer.

If the heatsink does not make good contact with the top of the processor,
then the processor gets hot, but the heat is not transferred to the heatsink.
The heatsink cannot do its job, unless the heat moves from the processor
to the heatsink.

This doesn't look like one of the troublesome designs, so perhaps
it isn't the problem. But I'd still visually inspect the fit of
that heatsink. (Make sure the heatsink is flat and not tilted.)
Also verify that the fins are clean and the channels are not
clogged with hair or compacted dust.

There is one Intel design, that uses plastic parts, and a cam
action. The plastic can snap.

Another design uses push pins, and the push pins can pop out of
place.

So there are a few designs, where the heatsink ends up not firmly
fastened.

The amount of force necessary, consists of two components.
Enough force must be applied, so that the heatsink "beds" in the
tnermal interface material. But a larger amount of force is
called for, to keep the heatsink in place, if the computer
is kicked or dropped. So part of the retention force is
to help keep the thing in place, even if the computer
receives a mechanical shock. If the forces involved are
too great, sometimes the clips snap or let go.

Holding the fan in place, is another issue, but not quite
as critical. For a fan, as long as the air exiting the fan,
is all passing through the fins, it should work well. If
the fan is so sloppy there are big air gaps, then valuable
air pressure can be lost. To force air through the fins,
the fan generates a bit of pressure, as the air has to
move with a good velocity to do the job.

Paul

 

[Paul]

OK I did look and the heatsink was ajar a bit (I don't think it was from the
entire desktop itself---it probably got jostled when I was taking off the
fan). I pushed it back onto the CPU, replaced the fan, but then the desktop
(with the fan running) shut down 5 seconds after being turned on again.

 

[R. McCarty]

There has to be a "Tight" fit. Just re-orienting the heatsink won't work.
Sometimes you have to remove the entire assembly clean away the
thermal paste and apply a fresh run onto the CPU heatspreader. Not
an impossible thing for a novice to do, but does have some risks. It's
possible that repositioning the heatsink has left a small air gap that will
prevent heat from being dissipated off the heat spreader.

 

[Leythos]

OK I did look and the heatsink was ajar a bit (I don't think it was from the
entire desktop itself---it probably got jostled when I was taking off the
fan). I pushed it back onto the CPU, replaced the fan, but then the desktop
(with the fan running) shut down 5 seconds after being turned on again.

If the heat sink was loosened and not making good contact, there is also
a good chance, depending on the age of the heat-sink paste, that no
amount of putting the heat-sink back on will help without also replacing
the heat-sink paste.

If it was not shutting down like this BEFORE you started messing with
the HS/CPU, then the problem is poor heat draw from the CPU through the
Heat Sink.

http://computershopper.com/feature/75-pc-building-tips-cpu-heat-sink-
installation

read items 29-31 in this article - you may have to fix the URL if it
doesn't copy properly.

 

[Paul]

OK I did look and the heatsink was ajar a bit (I don't think it was from
the entire desktop itself---it probably got jostled when I was taking
off the fan). I pushed it back onto the CPU, replaced the fan, but then
the desktop (with the fan running) shut down 5 seconds after being
turned on again.

But there should be something holding it in place. It doesn't just
sit there. The latches are supposed to be hard to fit. You hook
one end on first. Then the end with the handle goes into place
second. (The little handle is there, to give you some leverage.)
The springy bit in the center is going to resist while
you're trying to snap the second hook into place.

If any of the four plastic retention eyes are snapped, then there
will be nothing to hook the clips to.

So you should have two clips, four ends to hook down, and the
heatsink should then be held in place. When thermal paste is
used on the CPU, sometimes the heatsink can be rotated a bit,
but you shouldn't be able to lift up on the heatsink and
have it come away from the CPU.

http://support.dell.com/support/edocs/systems/dim2350/replac73.jpg

Paul

 

[Paul]

OK that took care of it. I got the thermal paste, but because the "plastic
retention eyes" were not all there, the heatsink itself was not held firmly
to the CPU. After getting a new 478-pin heatsink retainer (with the
retention eyes), I then glued the heatsink back on and all has been well.

Thanks everyone for your advice.