Strange Computer Problem

[n2ize]

I have a Dell 4600 desktop / tower system that I use for most of my work, It's several years old now but still serves me well.

A weird problem just happened. I was doing some work and the system just completely froze on me. I had to hit the big switch to reboot it. But, it wouldn't reboot. Nothing would start or initialized. It would just sit there giving me a series of long beeps. Upon looking at the trouble indicator lights on the back of the machine they were all out. According to the manual when all the lights are out it indicates some sort of "pre bios failure". There is no recommended fix for such a problem in the manual.

I disconnected everything from the machhine and put it up on the workbench and opened it up. I hooked it up to a test monitor, plugged it an and, all of a sudden it works. All the trouble lights are now on and green and there is no error beep.

Any ideas what might have gone wrong ? Could it be a possible overheating ? The temperature in the room is quite a bit warmer today than it has been in a while. I am wondering if the CPU was overheating and the system threw itself into "protection mode".

I also notice that the CPU cooling fan wasn't making much noise. Usually with the case closed the fan really starts running fast (sounds like a power blower) to cool down the CPU. This time the CPU fan was idling along quietly, much as it does during the winter months. The question I have is why would the circuitry responsible for raising the fan speed in response to temperature rise not be doing it's job ?

Of course all this is assuming that the problem was due to an overheating condition to begin with.

Any suggestions / help appreciated.

[N9FE]

My sound card arched over during a very hot and humid week last summer. Kinda did what yours did. So now i clean the dust out more often, And take a eraser to the contact pins.

[n2ize]

I gave it a cleaning. Seems to be running okay now.CPU fan seesm to be adjusting speed in accordance with CPU temperature.

[n0iu]

Stuck key?

[n2ize]

Stuck key?

I thought of that. But it turned out it wasn't a keyboard problem. Even with the keyboard and mouse , network, USB, etc disconnected the machine still wouldn't boot. The BIOS wouldn't even initialize. The machine has 4 lights in back labelled A B C D, and each light can be in 3 states, green, amber, or off... giving a total of 81 possible codes of which Dell only used a few. In this case in addition to the error beeps all 4 indicators were in the off state...which according to Dell indicates a "pre-BIOS failure".

Funny thing was that once I disconnected the machine and opened the case and tested it everything came up normal and all 4 lights went green indicating a properly functioning system. Only explanation I can think of is an overheating condition. I did clean a lot of dust out from inside and from around the front vent holes.

[KF2M]

It could have been an overtemp condition, by any chance you take a good look at your caps? Dells from several years ago had a nasty habit of caps leaking or going bang. Generally it starts off with some form of video glitch, or memory errors.

[n2ize]

It could have been an overtemp condition, by any chance you take a good look at your caps? Dells from several years ago had a nasty habit of caps leaking or going bang. Generally it starts off with some form of video glitch, or memory errors.

No, no memory or video problems. I think the machine was overheated. The vents were blocked with dust. And the CPU fan didn't seem to be picking up speed in correlation to the increased CPU temp. Now it seems to be okay.Fan seems to be responding to the thermal sensor.

[W3WN]

I have a Dell 4600 desktop / tower system that I use for most of my work, It's several years old now but still serves me well.

A weird problem just happened. I was doing some work and the system just completely froze on me. I had to hit the big switch to reboot it. But, it wouldn't reboot. Nothing would start or initialized. It would just sit there giving me a series of long beeps. Upon looking at the trouble indicator lights on the back of the machine they were all out. According to the manual when all the lights are out it indicates some sort of "pre bios failure". There is no recommended fix for such a problem in the manual.

I disconnected everything from the machhine and put it up on the workbench and opened it up. I hooked it up to a test monitor, plugged it an and, all of a sudden it works. All the trouble lights are now on and green and there is no error beep.

Any ideas what might have gone wrong ? Could it be a possible overheating ? The temperature in the room is quite a bit warmer today than it has been in a while. I am wondering if the CPU was overheating and the system threw itself into "protection mode".

I also notice that the CPU cooling fan wasn't making much noise. Usually with the case closed the fan really starts running fast (sounds like a power blower) to cool down the CPU. This time the CPU fan was idling along quietly, much as it does during the winter months. The question I have is why would the circuitry responsible for raising the fan speed in response to temperature rise not be doing it's job ?

Of course all this is assuming that the problem was due to an overheating condition to begin with.

Any suggestions / help appreciated.
Defintely sounds like a heat problem. Cleaning out the dust bunnies is always a good thing. Make sure that the fan on the PS is actually working... if it's started to go, or has died, you have no air circulation inside the machine, and it will overheat.