Computer only Boots when Ethernet is NOT Plugged in

[DodgerKing]

This is interesting. One of my PCs will only boot up when the Ethernet chord is not plugged into the computer. When it is plugged it, the fans will start up for a few seconds and then power down for a few seconds, and this cycle keeps repeating. Once I unplug the Ethernet cable, it will start up with no issues at all. I have tested this out numerous times at work, my house, and my parents house. The same thing at all three.

 

[diogen]

Net boot ROM enabled? Tried clearing CMOS?
Used different net cables?

Diogen.

 

[DodgerKing]

Reset the bios. Used a different cord each time since I was in different locations.

It was working even after flashing the bios. Reset the bios and still worked.

Network card went out?

 

[diogen]

Network card went out?

Very likely. Maybe a short.
Blow compressed air into the plug...

Diogen.

 

[DodgerKing]

Just checked the setup. No network boot enabled.

I'll take it home and see if I can reinstall the drivers that came on the CD

 

[diogen]

Bad drivers can't prevent boot.
They are OS specific and get involved much higher in the "food chain"...

Diogen.

 

[DodgerKing]

Bad drivers can't prevent boot.
They are OS specific and get involved much higher in the "food chain"...

Diogen.

It is definitely a hardware issue or BIOS issue?

 

[diogen]

I think so...

Diogen.

 

[DodgerKing]

I'll see if our tech here has any extra cards lying around that I can use to trouble shoot.

 

[diogen]

Is it a desktop or laptop?

If desktop, disable the network card in BIOS and install a discrete (PCI or PCI-Ex) one.
With laptops this isn't always possible but using something like an external USB-Ethernet adapter should work.

Diogen.

 

[mike123abc]

I would say that its a power problem on the motherboard. When you make the connection it sends power to the ethernet adapter interface, probably a power spike came in through the ethernet port and weakened a component.

 

[DodgerKing]

Is it a desktop or laptop?

If desktop, disable the network card in BIOS and install a discrete (PCI or PCI-Ex) one.
With laptops this isn't always possible but using something like an external USB-Ethernet adapter should work.

Diogen.

Desktop.

This is one of the PCs I built myself. I do have PCI express x1, PCI x4, and PCI express x16 slots on the motherboard

 

[DodgerKing]

I would say that its a power problem on the motherboard. When you make the connection it sends power to the ethernet adapter interface, probably a power spike came in through the ethernet port and weakened a component.

So it could be a short anywhere on the motherboard?

This computer has been left on for over 5 years, pretty much 24/7. I used it as my main network computer and pretty much never turned it off. That is a lot of hours on the board

 

[mike123abc]

So it could be a short anywhere on the motherboard?

We had a lightning strike once that blew the ethernet ports of a bunch of machines. It was probably an induction issue because it was on the machines with the longest runs of cables. The machines worked fine but the ethernet ports were non functional. The ones that had discrete cards were easily fixed, but the ones on the motherboards required discrete cards to be added.

I could not see any damage on any of the cards or motherboards, they looked perfect, so I assume it was internal to a component. They are low voltage parts and probably could not handle the surge.

Now ethernet is built in fuction of the cpu chipset, so I can see how it could cause the north/south bridge to fail if a connection is made.

 

[diogen]

I would say that its a power problem on the motherboard.

In this case - considering the PC is 5 years old - trying a different power supply wouldn't hurt...

Also, if you haven't done so, try opening the case and clean inside.

Diogen.

 

[DodgerKing]

In this case - considering the PC is 5 years old - trying a different power supply wouldn't hurt...

Also, if you haven't done so, try opening the case and clean inside.

Diogen.

Already did that. Switched out power supplies and the same exact issues.

BTW, my computers are always clean inside. I make a habit of cleaning them once every few months (the only time this particular computer ever gets shut down)

 

[DodgerKing]

Another thing. Restart gives no problems. Turning it off for an extended time, and then starting up gives me this issue or disconnecting the power and starting it up gives me the problem

 

[diogen]

Another thing. Restart gives no problems.

What do you mean?
Starting without, connecting Cat6 and then restarting works?

That would mean power issues. How many drives do you have?

Diogen.

 

[DodgerKing]

What do you mean?
Starting without, connecting Cat6 and then restarting works?

That would mean power issues. How many drives do you have?

Diogen.

I mean selecting restart in the start menu vs shut down (for extended period of time) vs disconnecting the power all together. The latter two give me the issue, the former does not. With LAN connected in all three scenarios

 

[Pepper]

One thing you haven't mentioned, after a successful bootup and replugging the cable, does the network function correctly?