Computer keeps re-booting

Lately, my computer has been running slow, but this morning the
computer wouldn't go to Windows. It just kept re-booting. I read
overheating can be one problem so I checked inside and it is fairly
dust-free. The fan is working, although it makes a high-pitched noise.
The cpu temp. runs about 104 degrees. I don't know if this is too high
or if it's a normal temp.I noticed a lithium battery on the
motherboard. I think it runs the clock but i wasn't sure if a bad
battery can also co tribute to a slow or overheated computer.Any
suggestion on what to check?

 

Start looking for malware, virus etc.

 

I've tried to do that by using safe mode, Windows still won't come up.
Can i check it in the CMOS setup utility window? I just checked in
the advanced BIOS features and anti-virus protection is enabled.

 

I just noticed what looks like another fan. It's called a sleeve
bearing, but it's not operating. Could this be causing overheating?

 

So far, you haven't identified the brand and model number of the
computer, or whether it is a home built machine. Or the OS you are
using.

If we knew what machine, or could find pictures, it would make it
easier to answer.

If the fan is on the chipset heatsink, it would depend on the era
of machine, as to how important it is. On old machines, the chipset
dissipates maybe 2W. The fan is not quite as critical there. Some
of the newer machines, have 20W power dissipation, and the fan
must be running if you expect stability.

The units of temperature are important. If it was "104 C" , then
the chip would be overheating. If it was "104 F", that is barely
above human body temperature, and not a problem.

The TCAV setting in the BIOS, is of limited usage. For malware
protection, you want to add software to your Windows install.

http://www.streamtech.net/Mainboards/Slot 1/P2B_series/P2B/index.htm

"...also include an anti boot-virus (TCAV ; TREND Chip Away Virus)
BIOS which can protect your system from being infected by boot-type
viruses during startup."

Some antivirus companies, provide a download of their product which
will operate for an evaluation period (30 days). If you have a
malware problem, you can use the evaluation period to clean
the machine of the virus. I did that using Kaspersky, and
when the trial period was up, I bought a copy at Best Buy.
It is a fairly annoying product, so you always know it is
there.

Since Windows is not coming up, it may be difficult to install it :-(

The CMOS coin cell will not make a slow or overheating computer.
on some computers, if the battery is below about 2.4V, the
computer may not POST properly. In that case, you may not see the
drive light flashing at all. But if there is some attempt to boot,
and some number of files are loading, before it croaks, then the
battery is probably not involved.

I can see a couple possibilities besides malware.

You could have bad electrolytic capacitors on the motherboard.
These affect the stability of the CPU, and the computer might
crash. The second hardware possibility, is a problem with the
power supply. On some machines, just as the desktop is about to
appear, the extra load on the power supply "tips the machine over",
and causes a restart.

To check for bad caps, you're looking for stuff like this.
These are on the motherboard, and probably near the CPU.
There may also be a brown stain on the PCB, near the base
of the capacitor - that would be escaped electrolyte, a liquid
which eventually dries and leaves a stain.

http://www.badcaps.net/images/caps/kt7/image004.png

Paul

 

This is my sons computer he bought at PC Club. I don't know if this is
a model but it says AMD Athion. The chip has the letters MSI. The
computer must be at least five years old if not older. I'll follow
your advice and see what i can do. Many thanks.

 

I knew I forgot something. The second possibility, is the power supply.
In terms of computer failures, they are probably number one. Hard
drives are pretty frequent, but a bit easier to guess at, as the
source of a problem. Motherboard cap failures cover a period of
several years, where bad batches of electrolytic capacitors
were manufactured. Some motherboard brands are worse than others
(one, in fact, resulted in a successful class action suit).

For the motherboard, you can try a visual inspection.

For a power supply, a multimeter can be used to measure the
voltages, or alternately, and just as valid, is swapping
another supply in place. Not every power supply problem lends
itself to detection with the multimeter. (Like a problem which
is intermittent, a bad connection that lasts a fraction
of a second.) I have one spare I keep here, for such
emergencies. Not a very good supply, but good enough for a
2 minute test.

HTH,
Paul

 

You could have bad electrolytic capacitors on the motherboard.

Thats the most likely problem have had that happen with a lot of
machines and the real answer is a new MB but that may well require a new
processor etc. The caps can be replaced but is a piggy of a job to do!..

Also you could try another power supply these are a number one suspect
for this sort of problem..

 

Good info again. Thanks. I have a question on the power supply. I'm
assuming the fan inside the power supply is independent of the power
supply itself, because the fan runs. But the power supply can still be
bad? Just trying to educate myself.

 

I just noticed what looks like another fan. It's called a sleeve
bearing, but it's not operating. Could this be causing overheating?

I am not sure exactly what you are talking about, but if that fan on
top of your processor chip is not functioning, it can easily result in
overheating and reboot failure. A new one is maybe ten bucks and
a little heat transfer compound.

The main power supply can be experiencing failures even if the
fan is running, and this is a common cause of problems in aging
machines.

HTH

 

The most common causes of rebooting:
Overheating: if your CPU fan is spinning, has not come loose off the
processor, and the side of the case is open your machine is not overheating.
More likely:
Dying hard drive or power supply, most likely the latter.
Dying hard drives tend to cause random BSODs as they fail if it is your C
drive. It would behoove you, if you can connect the hard drive to another
computer, to back up your files before you doing anything else.

 

The fan is usually powered from some source of +12V. If you heard the
fan, it might mean that +12V worked. But you wouldn't know about the
others. Since control of the supply is tied to +5VSB, you can have
supplies that switch themselves on and off (oscillation), because
of a problem with PS_ON# or with the +5VSB second power supply.

By showing you the following picture, I'm not hoping to turn you into a
circuit engineer, but this shows the basic flow of the ATX supply.
You're right, in that the output stage is pretty simple, so it is
unlikely the +12V would work, and the +3.3V or +5V wouldn't.
Maybe if an output filter cap was bad, there'd be excessive ripple,
which could upset the PC. In any case, you can have a glance at this,
to see what they hide in the "box". This is the only schematic I've
ever seen for one of these, and the author of this web site prepared it
by tracing the circuit by hand.

http://www.pavouk.org/hw/en_atxps.html

Paul

 

Paul has passed on some good advice.

If that fan is on the CPU heatsink then it needs sorting out before
anything else.

If the temperature you quoted was in degrees centigrade then thats very
bad. The Athlon CPU will not last long above 90 centigrade.

 

Now Paul, that is just downright cruel.

I used to repair the dam things! Fortunately it is now less costly to
just bin them. That PSU design must go back 15 years or so. DTK was a
good manufacturer to work with, knowledgeable engineers that bent over
backwards to help you when you needed it.

Are they still around ?

 

The cpu fan works but it makes noise. I might try oiling it first. The
one that doesn't work is the case fan, the one at the back. I think
this might draw the heat out of the chassis. I'll try fixing the fans
first before i spend more money. Hopefully it just the fans.I did see
the temp.got up to 111 degrees about 5 minutes after i turned on the
computer. Regards.

 

Ive had this happen from a fan not functioning or cooling fins that are
plugged
with dust bunnies.

Hard drive problems can be an issue. I went through that with dammittohell
Windows and the hard drive wasnt really the problem. The software
caused the issue. Reformatting and reinstalling corrected the Bill Gates
abortion.

Microsoft is no friend of mine.

 

Here's an update. I was trying to locate the whirring sound inside the
case.Thought it was a fan but i isolated it to one of the hard drives.
The other one runs quiet, so i wonder if this is a symptom of a bad
hard drive which could be causing my re-booting.? What happens now
when the computer is re-booting is i get a one second hum (a surge
maybe?) then a quick blue screen with text on it. It's only visible
for a split second, then the cycle starts over. I use compressed air
today to get rid of the dust. All fans work except the case fan. I
haven't done any electrical testing yet. Just trying to check the easy
stuff first. Regards.

 

Disk drives do not cause rebooting. Is a drive defective? Then
what do system (event) logs say about the defect? What do the logs
state about the reboot? IOW get facts long before suspecting any
component. What does Device Manager report? What do the comprehensive
hardware diagnostics (provided free by responsible computer
manufacturers) report? You have no reason to suspect anything yet
because the only facts are rebooting and a noise. Neither identifies
any part as defective. Any conclusion from those two facts is only
wild speculation.

If the chassis is open, then computer should work with no chassis
fan running and the room temperature at 100 degrees F. Trying to cure
a reboot problem by clearing dust is simply curing symptoms. Heat is
used to make failures harder - so that failures can be easily locate
by diagnostics. Your computer with dust should work even when room
temperature is 30 degrees higher. If not, then a hardware problem
exists. Blowing out dust only 'cures symptoms' - does not solve any
problems.

 

I had exactly the same problem , the cure for me was this .:

First disconnect power supply and remove all cards ide cables and ram
Next get the hoover and clean the board of any dust and suck out all
slots .
Get some isopropyl , ( square shaped medical swabs are ideal ), and
clean all the copper contacts on each card , and also fold a swab in
half and push it into all the slots and clean inside , including ram
slots , everything even rub over the board just get everything very
very clean . Hoover once more .
Now replace everything and reboot , enter your bios and choose fail
safe options .

You can try booting at this stage , but i strongly recommend you to re-
install windows, just to eliminate a corrupt registry

This worked for me .

 

If it helps, I have found faulty RAM to cause this. Also, if the CPU
fan is not properly seated, the CPU will overheat tripping the thermal
shutoff.