CMOS keep reverting to factory settings

[john D]

I am trying to repair an 2006 INTEL CELERON CPU (2.80Ghz, 224Mo RAM,DD 80GO,XP PRO SP2) from a friend that a lot of pro repair people just gave up on.

The first thing noticeable was the CPU fan ran like crazy upon startup and receeded to a normal rate/noise only after 10 seconds or so when the operating system started booting. During these 10 seconds, the POST screen displayed "CMOS settings wrong" and "CMOS date/time not set".
When Windows booted,it ran EXTREMELY slow and the HDD was EXTREMELY noisy;a first AVAST scan on partition C didn't show anything, so i tried to install adaware, but it stopped upon installation with the pop up alert " not enough virtual memory".

So i figured the 256 RAM was bad, and that Windows was using the HDD itself to increase the virtual memory, hence the noise and the slugginess.I bought two new 500 Mo RAMS and installed them, plus i replaced the motherboard battery in case it was dead ( and i did it right).

The computer ran better,even though Windows appeared still slugish and slow responsive, the new memory got recognised, but the CPU was still going crazy at startup and the HDD was still noisy. I didn't notice any deleted/ corrupted files.MSN messenger couldn't connect with the username/ password stored. After a few shutdowns/ reboots, i noticed the CMOS settings suddenly reverting to original factory values and the floppy disk disappearing in windows ( even though it was detected in the BIOS).Then came the time when the computer booted but the screen remained black, as if the motherboard was dead.

Figuring a hidden virus was still on the HDD, i removed it, hooked it in an external case to another computer and ran AVAST again; it found a Win32 Sdbot family virus on the partition D not scanned previously; it's threat was considered, depending on the various internet sites, from moderate to extremely high. It was designed to be a backdoor for taking complete control of the computer.A second ensuing scan with VIPRE found the drive clean.

I replaced the HDD in it's original place, the computer booted but i got a dead black screen again. Out of desperation, i reseted the CMOS by both taking the battery out for 10 hours and displacing the CMOS jumpers.

The computer screen lit and windows booted. After a few reboots, again it refused to lit. Again, resetting the CMOS settings would accomplish the trick.

In order to determine if an unknown virus was still hidden in the HDD and affecting the CMOS settings, i unhooked it and ran the computer without any booting device; the CMOS settings kept resetting after being set.

I reckon either a VIRUS infected the BIOS and keeps resetting the CMOS settings and make the CPU fan run crazy, either the BIOS have gone bad.
( the CPU fan recedes to a normal speed once the bios have transfered the boot sequence to a booting device, removed in this case: i got a message asking to select a booting device, and the CPU fan receeds at that precise instant).

At the same time, BIOS viruses are extremely rare; could it be just the BIOS have gone bad ?

Is there an antivirus boot disk i could use to disinfect the bios ( by setting the first boot device to floppy or CD/DVD drive) ?

Should i flash the BIOS while a Virus is lodged there ?

Will Darik's Boot and Nuke completely secure erase an infected drive ?

[Guts3d]

It sounds as if you have a few problems here, not just a single error. One thing to check; the CMOS battery you installed, is it new? Is it fully charged? Also, check the jumper on the hard drive; if they are set wrong it will give slow or no performance. A quick check of the capacitors on the motherboard will tell of any leakage, and I would go ahead and update the BIOS on this one, if it were mine. Good luck!

[john D]

It sounds as if you have a few problems here, not just a single error. One thing to check; the CMOS battery you installed, is it new? Is it fully charged?

Brand new, out of the box.

Also, check the jumper on the hard drive; if they are set wrong it will give slow or no performance.

It's a sata drive

A quick check of the capacitors on the motherboard will tell of any leakage,

They al look pristine; this computer has been on different shelves for the last 3 years and was hardly used.

I would go ahead and update the BIOS on this one, if it were mine. Good luck!

OK; who dares wins....(hopefully)

[CCT]

During boot, before the OS takes over, the cpu fan will run full tilt if the CMOS has been reset, ie, no thermal operating speed/ranges are set for the fan.

The fact that you keep getting CMOS resets is indicative of a hardware malfunction.

Next time you can boot to the OS, run Memtest86 for 7 passes to check the Ram, and also run Everest or similar to check temps and voltages (you can save a report for those under Computer-Sensor-reports).

http://www.filehippo.com/download_everest_home/

http://www.majorgeeks.com/download4181.html

http://www.softpedia.com/progDownloa...oad-16369.html


A Bios update should be a last resort since failure of that and you are out of business for a while at least.

[melee5]

You still need to verify the CMOS battery voltage, they can die in the box just as easily as anywhere else. Volt/ohm meter time.

Just removing the battery for a set amount of time might not do the job. Substitute the battery for a wad of aluminum foil so as to short any remaining charge across the battery terminals of the motherboard to zero potential and then start your death watch. I have nothing but respect for the 10 hours you gave it last time. Some Dallas timer sockets have micro batteries in the socket itself, thankfully they don't much juice so the tinfoil will defeat them.

[Platypus]

Valid comments, melee.

Over the years I've also had a couple of instances where CMOS data was not retained because backup battery power was not reaching the CMOS RAM. One where battery leakage had eaten through a track on the board, another where a current steering component (Schottky diode) had failed. And of course it's also possible for the RTC clock chip where the CMOS memory resides to have suffered a failure.

[john D]

The funny thing is i suspect the motherboard is draining the power of the battery: the voltage of one battery got seriously drained after placing it for 2 hours; has anyone encountered this before ?

Here are the voltages given by Everest:

Valeurs de voltage:
Noyau CPU 1.32 V
+5 V 1.32 V
+12 V 9.66 V
Mise en veille +5 V 1.17 V
Debug Info F 9B 57 FF
Debug Info T 28 32 32
Debug Info V 81 00 00 31 97 C5 96 (03)

[CCT]

If those readings are accurate, your power supply unit (PSU) is toast.

Can you verify them with a multi-meter?

Running with voltages that low will damage some components.

If you don't have a multi-meter or know how to use one to verify voltages, I would urge you to take the comp to a shop and have them do it.

[john D]

If those readings are accurate, your power supply unit (PSU) is toast.

Can you verify them with a multi-meter?

Running with voltages that low will damage some components.

If you don't have a multi-meter or know how to use one to verify voltages, I would urge you to take the comp to a shop and have them do it.

I don

't know how to use a multi-meter, but i have no reason to believe Everest is wrong.
I can try replacing the PSU and see what voltages i get then.

[NooNoo]

I would go with a replacement power supply first as well.

[john D]

If those readings are accurate, your power supply unit (PSU) is toast.

Can you verify them with a multi-meter?

Running with voltages that low will damage some components.

I've heard about components damaged by power surges, but never low voltages.
Are you sure about that part ?

[NooNoo]

Yep!