Mysterious Computer Problems

Well, my computer is really getting funny.

So I want some help playing computer detective.

First the graphics card went out, so I bought a really cheap new one and everything worked fine.

Secondly the integrated ( on the motherboard ) network card stopped working. I bought a really cheap new one and everything is working.

The other day, the screen went was black but it sounded like the computer started up fine.... so I turned it off, carefully reinserted the graphics card and network card and voila it worked fine again.

Now yesterday for the first time the screen went black during use.... and the music it was playing stopped. Now when I start it up it sounds like starting up normal but screen is black.

After re-inserting the cards like I did last time it is still not working.

I am getting really tired of this machine.... but still I guess it would be a bit of a pity to trash it. Anyone have any guesses on what has gone wrong with it? Perhaps the MB is about to break ? or is it a powersupply problem causes components to break one after another or something else?

My first guess also was a powersupply that may be too weak for what you are running? Another problem I once had that led to completely erratic problems for a while before the computer died for good had to do with failing (leaking) capacitators on the MB. Do you have any that look like they are bulging / leaking?

It looks like a Mainboard issue.
Power supply either works not at all (e.g. when it's broken) or freezes/crashes the PC when the required power level is higher than the one provided. You should be able to test the PSU by simulating a high work load with some 3D benchmark tool.

It could also be a graphics card problem or a RAM problem. The symptoms you described are not really all the specific to a certain part of the PC.

The graphics card is almost new... so I guess I should have a guarantee on that.... but I don't think there is any good way to pinpoint if it really is a graphics card problem or not... without trying with another graphics card ? or trying my graphics card on another PC?

PSU or mainboard general issue from your description.

Could potentially be RAM as well, and you can test that by removing individual sticks of RAM (unless you just have 1 stick) - and it's a pain to be certain.

Lastly, it can be the CPU - which may or may not suffer from a heat-related issue, and it's one of the pieces that are required for your MB to do anything at all - which may be the reason it won't boot now.

I can actually recommend taking everything apart and carefully putting it all together again, and cleaning fans/reapplying cooling paste etc. Sometimes a bit of loose wiring can block fans, or just cause general instability without you noticing it.

If you get it booted, try running demanding benchmarks for extended periods of time, to be sure.

When there's no apparent cause - I find it helps to NOT speculate, and just test everything meticulously - even if you think you've eliminated it from being the issue.

Well, the strange thing is it boots, up the fan boots up ok, and so on. But the screen is black. If something was really broken I think the MB should warn somehow. This is what makes me suspect the graphics card. But on the other hand it has been acting dodgy and strange for quite some time. It might be the MB acting dodgy so the PCI-express bus is not working as it should.

I can actually recommend taking everything apart and carefully putting it all together again, and cleaning fans/reapplying cooling paste etc. Sometimes a bit of loose wiring can block fans, or just cause general instability without you noticing it.

Click to expand...

Well, this is what I did, and after I put it back together it was working fine.... for sometime until now when it broke again. Perhaps it is some kind of glitch somewhere?

Well, this is what I did, and after I put it back together it was working fine…. for sometime until now when it broke again. Perhaps it is some kind of glitch somewhere?

Click to expand...

Unfortunately, it's really hard to say.

Since it seems to have worked for a little while and then stopped - it sounds like a heat-related issue to me. The CPU is one possibility. If it runs a while and then stops - with the fans/power running after you power it up, it may be that it's running hot and that will prevent the system from getting to the video card boot stage - since the CPU is needed for that - which may be why you're getting a black screen. The CPU fan might be faulty or the heat might not get redirected due to the metal not connecting right with the paste etc.

It could be fried, and then you're screwed.

Can't really help you much more though, since it can be PSU and the mainboard as well. Best thing is if you have a friend willing to let you test stuff with his/her machine - and you can test parts like the video card.

Yes, I'm going to go ahead and order a new monster machine since I need at least two working machines, one older for testing and one newer for game developing Now my new machine can become my old one......

If I can fix the old computer.... well, I can give it to someone in need of machine.

Thanks a lot for the help! If anyone have yet another idea that is of course welcome. I hate trashing things which could be easily fixed.

Most was already answered by my distinguish colleagues.
Usually those symptoms are caused by motherboard failure. When the failures are erratic, usually it's a swollen capacitor (or a group) of them.
It can be also a problem with a PSU. In third place I'd go for the graphic card or a problem with the graphic card slot. Fourth I'd check the CPU cooler support they tend sometimes to break. Fifth RAM, in that case try to use only one stick each time in different slots. Don't forget to unplug the dvd/hardisk cables (both cables, data and power).
The CPU itself, normally don't get affect. In more than 20 years of professionally doing PC repair, I haven't seen more than a couple of times a CPU damaged. Intel only once.

This is a image of a swolen capacitor:
.
Check all, specially those near the graphic slot.
Could you please, post an inside photo of your computer?


EDIT:

GothicGothicness said:

The graphics card is almost new… so I guess I should have a guarantee on that…. but I don't think there is any good way to pinpoint if it really is a graphics card problem or not… without trying with another graphics card ? or trying my graphics card on another PC?

Click to expand...

Could you do that? That would help in knowing if it's the graphic card or not. I've seen some weird coincidences happening during my professional activity.

My first guess is psu when anything "mysterious" starts to happen and seemingly unrelated components develop issues.

Perhaps, here is adding to the mystery as I experimented some more.

Removed network card… it worked. Put in network card agian… didn't work… took it out again and it worked again. So I thought AHA, got it… it is something wrong with the network card. Tried it in another slot… still didn't work… removed it and… it didn't work. So it appears to be kind of random whatever it works or not. Strangly after it starts up it appears to be running fairly fine…. so I think I can rule out the graphics card at least?

I also found that if it works.. I can hear the going in to bios beep immidietly knowing that it will work, if it doesn't work there'll be no going into bios beep… thus it appears to not even reach the bios….. really weird.

One thing seems clear, the network card is fried. And when a pci device fries the computer might not start and have the symptoms you're mentioning.
Remove every pci device from computer, and only insert the graphic card.
Do you know how clear cmos? There a jumper, usually, when removed or inserted in other position, it will clear the bios. Other way is unpluging the psu from power and removing the battery from the motherboard (1 hour usually is enough).
If this is complicated, tell me which motherboard you have, and I can try to download a manual and help you in the jumper case.

GothicGothicness said:

Perhaps, her is adding to the mystery as I experimented some more.

Removed network card… it worked. Put in network card agian… didn't work… took it out again and it worked again. So I thought AHA, got it… it is something wrong with the network card. Tried it in another slot… still didn't work… removed it and… it didn't work. So it appears to be kind of random whatever it works or not. Strangly after it starts up it appears to be running fairly fine…. so I think I can rule out the graphics card at least?

I also found that if it works.. I can hear the going in to bios beep immidietly knowing that it will work, if it doesn't work there'll be no going into bios beep… thus it appears to not even reach the bios….. really weird.

Click to expand...

Still sounds heat/power related to me.

All those things could just be incidental to the motherboard/CPU getting too hot while you're experimenting - or the PSU having trouble delivering the right voltages/whatever after certain potentially faulty components are overburdened. So, it might be components or the actual CPU - or it might not be related to any of those at all

Didn't you say the integrated netcard stopped working first? Could be the southbridge of the motherboard having trouble in general. Which would explain your new network card acting up randomly.

Thanks for the new advice... I will experiment some more with it! And post my findings....

GG when one part of your mainboard is out you have to assume the rest of it is out or too because this is how they act if you get that portion replaced. These are classic symptoms and why integrated boards were so controversial back in the day.

You probably got hit by a spike or (most likely) an accumulation of smalls spikes and brownouts. Anything plugged into the wall get these and its only so long before we all get them.

The feds only regulate 330, 400, and 500 volts as a clamping voltage which most surge protectors are. Since a spike happens at 140volts (your US wall socket runs at 120v) its obvious that 95% of surge protectors are useless. Small surges happen in the in an American household tens of thousands of times a year. Triplite makes one of the only (military grade) surge protectors on the market.

But a surge protector can't protect you from a brownout - when your periods of low voltage and power which can be worse.. For that you will need a battery backup or UPS (Uninteruptable Power Supply).

Anyway, my advice to you is to quit fiddling with individual components because the original problem is on the MB. The spike that took out the one part is has either hit other parts of the board or simply causing confusion and shorts in the rest of it.

Replace the board and symptoms will go away - a cheap one is often an upgrade to what most people have.

I am posting from this computer now…. with the network card plugged in and it is unusual hot for sweden in april today too. ( 25 C ) so I think I can rule out heating problems…. and network and graphics card problems. Yesterday it didn't work at all, but now it works... worth to note is I did nothing.

I guess it is power supply or MB. I found the best way to fix something though… is to order something new…… because I placed an order on a new computer just today…… and this old clunker works like a charm so far after that Good excuse to get a new almost top of the line machine either way. If this one keeps working well I can always give it away. Thanks again for all the help.

I am not expecting this to last… but if it does…. well that is kind of scary!

I had almost exactly the same problems like you had, GG, and the source of the problem was almost exactly the same that Von Paulus posted.

I bought a new PC instead, rather than a new motherboard. (And that was in 2007.)