Computer won't boot the BIOS

[tel190]

Computer was working fine last night. This morning nothing appears on the display at. The power light is on at the front, the CPU fan is running, the HDD is spinning and the DVD drive light comes on. It seems to make no attempt to boot the BIOS and there are no beeps.

I have tried:

Resetting CMOS (3 different ways!)
Reseating the RAM
Tested the HDD in another machine
Installed a different graphics card (graphics is on board on this mobo)

None of those make any difference. It had a new PSU recently so I don't think it is that.

All ideas gratefully received.

 

[jacobweaver800]

Computer was working fine last night. This morning nothing appears on the display at. The power light is on at the front, the CPU fan is running, the HDD is spinning and the DVD drive light comes on. It seems to make no attempt to boot the BIOS and there are no beeps.

I have tried:

Resetting CMOS (3 different ways!)
Reseating the RAM
Tested the HDD in another machine
Installed a different graphics card (graphics is on board on this mobo)

None of those make any difference. It had a new PSU recently so I don't think it is that.

All ideas gratefully received.

You said you got a new PSU recently? What is the new PSU because that could actually be it, also did you make sure all the cables are plugged in correctly after swapping the PSU's

 

[tel190]

The new PSU has been working perfectly for about 6 months.

 

[jacobweaver800]

The new PSU has been working perfectly for about 6 months.

Ok, good. But what PSU is it, just because it worked for 6 months doesn't mean it actually works just fine. Also have you cleaned dust from your PC in those 6 months? Try cleaning any out of the PSU that could be causing it to short.

 

[tel190]

It is a 500W switching power supply ATX-500B. There no dust in the PSU, the fan blades are all clean as well. You see the internals through the grill of the PSU casing.

 

[jacobweaver800]

It is a 500W switching power supply ATX-500B. There no dust in the PSU, the fan blades are all clean as well. You see the internals through the grill of the PSU casing.

Ok, what brand and model is it. Fun fact, not all 500w PSU's can actually output 500w stabily or at all without killing everything in the PC. Which is why we need to know what your full system is, PSU brand and model too.

 

[tel190]

I can't remember the brand and I can't find it on the label but it was not a cheap one. It is a gigabyte GA-78LMT mobo and AMD FX4300 (I think, without removing the CPU fan and cleaning the CPU I can't be tell the exact number).

 

[jacobweaver800]

I can't remember the brand and I can't find it on the label but it was not a cheap one. It is a gigabyte GA-78LMT mobo and AMD FX4300 (I think, without removing the CPU fan and cleaning the CPU I can't be tell the exact number).

Exact model of the CPU should be listed in task manager if you go to the CPU tab under more details -> Performance -> CPU
Also, if the brand isn't listed on the PSU chances are it's off brand and almost definitely the cause. What was wrong with your old PSU that you had to upgrade?

 

[tel190]

As the computer won't even boot to BIOS I can't get to task manager.

I'll put back in the original PSU and see if it makes a difference. Previously the machine was randomly hanging. After running diagnostics for 3 days, once during those 3 days I got a single failure on the PSU but every other test and retest showed no problems anywhere. So I changed the PSU and the hanging has stopped.

 

[tel190]

I changed the PSU and it is exactly the same. So it is not the PSU or the graphics.

It is looking like the mobo, CPU or RAM, all of which are difficult to test without buying replacements. There is only 1 stick of 8Gb RAM so I can't easily test it.

 

[jacobweaver800]

I changed the PSU and it is exactly the same. So it is not the PSU or the graphics.

It is looking like the mobo, CPU or RAM, all of which are difficult to test without buying replacements. There is only 1 stick of 8Gb RAM so I can't easily test it.

I think you may have killed something by buying an off brand PSU. You always need to buy a brand name one no matter how expensive since it is dealing with every component in your PC and a short could kill your PC, and I've heard about house fires from off brand PSU's already

 

[tel190]

I have been using unbranded PSUs for 30 years and never had a problem. In fact the original one shipped with the computer appears to have been unbranded. I am certain that it is nothing to do with the PSU which wasn't a cheap one anyway.

The real question is how do I find out what component has died when I am getting no info from POST, the BIOS or anything?

 

[jacobweaver800]

I have been using unbranded PSUs for 30 years and never had a problem. In fact the original one shipped with the computer appears to have been unbranded. I am certain that it is nothing to do with the PSU which wasn't a cheap one anyway.

The real question is how do I find out what component has died when I am getting no info from POST, the BIOS or anything?

It doesn't matter how much you payed for the PSU if it's off brand or an untrusted brand. Off brand makers use cheap or defective caps in PSU's to make them cheaper, they usually use caps that were denied by big brands like EVGA because they can get them cheaper.