A very odd problem with my motherboard

[r2k]

I've got a Celeron 466 overclocked to 546 (78 MHz FSB) and i440BX-based MSI MS-6163 Pro which still provide me with a solid performance in my field of work(3D CAD).As I live in a warm city (Tehran) and as I wanted to max out my CPU I got a front case fan and it helped a lot(It did NOT support RPM readings though).
A couple nights ago,my PC suddenly shut itself down while I was surfing the net(It had actually hard-rebooted;my HDD and CD-ROM both powered up,but not even a single LED lit up on my keyboard and my monitor remained in stand-by mode.The helpful MSI D-LEDs on the mainboard all remained red: SOMETHING WAS VERY WRONG!I frequently monitor the heat produced by the CPU AND the Motherboard and my last read was 35c and 39c each.I've had 45c/49c at summer and it's worked perfectly...However I checked all the things I thought might have caused this and saw that the case fan didn't work.EVERY OTHER THING WORKED LIKE BEFORE.
Now,this goddamn problem remained even while I downclocked my CPU/FSB to the default 466/66.I conducted some experiments (stressing the system with some programs,like SETI,3D Studio MAX,and discovered that WHENEVER THE MOTHERBOARD GOES BEYOND 39c(AT THE VERY MOMENT IT REACHES 40 centigrade) either Windows starts displaying successive BSODs or the system simply hangs(or restarts and hangs there).This is getting worse because sometimes after powering down the PC and turning it on with the ON/OFF switch the problem remains(maybe still over 40 centigrade!?).What is happening?My CPU works(as I can see) flawlessly and its hottest temp has never exceeded 36c in its overclocked state(546 MHz).So is this going to be the motherboard (or the Slotket)?.Then why it's happened so abruptly?Did the f***ing case fan blow something on my mainboard when it went the way of the Dodo?Can anyone help
me please? I'm really screwed up...Please answer my two questions if you can,I'd appreciate it very much:
a)Why did this happen?
b)How can I remedy it?I don't have the money to buy a new Mainboard and I want to keep all I have for a bigger upgrade to a Duron.

And please don't tell me these things because I've double-checked them:
1.No voltage tweaks.Always at default 2.00 v.
2.No warnings/shutdowns on overheat enabled in BIOS or in any program.And mind you they were working perfectly before all this...
3.No Virus!Norton AntiVirus with every latest update available installed.
4.40 centigrade is NOT a high temp for a chipset.
5.It isn't the result of overclocking:If it was,why it waited a whole season after I hit 546 MHz and it ran rock stable with NO overheating?Why is it happening at the most conservative settings and at default speed?
Again thanks in advance for your replies...

 

[Guest]

You missed one ... Just for the heck of it why don't you do some voltage checks on your power supply. Won't cost anything and worth a Look.. ,o_o,

 

[r2k]

How do you measure the voltages on the power supply Shooter_1?
My MSI PC Alert III reports several voltage readings and I must say they are totally normal(compared to what I had seen before).These are the numbers when I reach 35c/39c:

Vcore 2.02v
Voltage(?) 1.49v
+5v 5.00v
3.3v 3.39v(it seems too high but it has always been this way.It may be higher than what it should be but it has never caused any problem)
+12v 12.10v
-12v -12.10v
5v standby 5.00v
Battery 3.06v

All are in the normal safe range I must say.I checked these when I was using the SETI@Home to stress the system and they remained more or less consistent(Vcore changed between 1.98 and 2.02 and 3.3v changed between 3.6 and 3.9 - just like every time I checked it before this).
Is this what you had in mind?If not,please suggest the correct way!The problem still remains...

 

[r2k]

My Power supply is a generic 300-watt one.For the Amp I can't read it easily becuase the specifications are on the top side and I should dismount the unit which I will as soon as I get time.
And actually I don't understand all this big deal about the power supply as the source of the problem.What do you think the power supply has done or is it damaged etc.?I myself think it's the motherboard itself and that's the reason I posted here...

 

[Guest]

Well I would think even a generic 300W power supply is more than enough for an old Celeron system. But don't discount the possibility that there is something wrong with it. I just finished a horrible month long experience building a new system in which I spent way too much time talking to tech support. They had me replacing my motherboard, ram, CPU, and the thing never booted. Only then did someone on this board suggest buying a cheap power supply to use as a sanity check and gee all of a sudden everything was fine. It's entirely possible your supply is dying and it is one of the cheapest components to verify.

 

[r2k]

You would never believe what it was.I solved it with a hint from a friend and my MSI D-LED diagnostics!I'm going to tell you what happenned (99% probability) in chronological order:
1.The case fan blew up.
2.The ambient temp got at least 10c warmer in my room because of the warm weather.
3.Things got too hot around the place on the motherboard that the CPU,BX Northbridge AND the SDRAM slots reside.
4.My CPU fan blew hot air right on the face of my SDRAM module(a PC100 CAS3 Spectek which I'd been running at 78 or 66 MHz CAS2 and can be considered a generic module).
5.Whenever my SDRAM chips got too hot (40c on the motherboard) the crazy things started to happen.
6.I'm happy to tell you I installed the module in the furthest slot from my CPU and it is working normally!
7.The problem was not my motherboard's RAM slots:When a crash happenned and the system wouldn't even start,I rapidly changed to a friend's SDRAM module and the system worked flawlessly right after that(even beyond 40c).
8.This was actually the most bizzarre thing in my experience with computers.If I hadn't checked the D-LEDs on my motherboard(they told me some times that the RAM was faulty but I dismissed the possibility as too odd) and the BIOS hadn't shown me this message: "Memory Test Failed" after one of those reboots,I wouldn't have known.

Thanks for all the other info guys;Seems you have to take good care of not just your CPU,but any other part in that hot case of yours!

PS:I suppose those of us in warmer cities have to overclock in winter only;Seasonal Overclocking if you'd like...

 

[r2k]

Sorry folks it has happenned again.This time I'm sure it isn't my RAM because I exchanged my old 64 MB CAS3 PC100 for a SpecTek 128 MB PC133 CAS3 but the thing has started to happen again (after more than 2 weeks of safe and sound computing).I'm really suspecting my Mobo this time because I can't think how a Power supply could fit in(or any other component for that matter).Ideas anybody?If I HAD to exchange my board should I go after a Duron?maybe get the same board?
BTW I'm still using the Celeron at its default speed...

 

[NickM]

First of all you are not able to implement thorough check
of your power supply just using simple tools.

You power supply generates some signals along with just
voltage/current.

There's high probability that some capacitor in the power supply fails.

You have to try another power supply. Replace it as the whole unit.

 

[r2k]

I WILL check the power supply along with the motherboard, but for God's sake why does it happen at a certain temp?!
Today I tested with my friend's CPU and it happenned again. I also changed my Slotket and used both mine and my friend's CPU with it and nothing...the bug's still happening.
All come down to the motherboard unfortunately ( or the power supply? ).I'm still open to suggestions...

 

[Ncogneto]

Well then why not just swap power supplies with your freind as well? It is easy enough to do. While you are at it test the video card as well. Remove all components except the video card for testing purposes.

A little bit of knowledge is a dangerous thing!

 

[r2k]

Good Point.I will do just that next time...
But where would the video card fit in?
I don't have any problem with my [crap old] Trident 9750.
No diagnostic program has ever told me about a bad video card...

 

[NickM]

Looks like your video's OK. But you have to follow the test procedure and try another card. Nobody knows.
Don't trust the diagnostic software very much.
Anyway, I use it.