ADSL renegotiates when certain pc in on

Hi, I have an odd situation which I thought I would ask on the forum, it is a problem that whenever my daughters pc is switched on causes the ADSL to renegotiate, and always causes the speed to drop too around 33% of what I get when the pc is not powered on.

When this pc is off, by think I mean that power is on and going into the power supply, but no running. As soon as the power button in pushed and the pc starts booting, the ADSL drops connection and renegotiates to around 1mbs. Why ever the pc is running, I cannot get the ADSL to go over this speed. As soon as the pc is powered down, resetting router to cause renegotiation brings the speed back to around 3mbs which is normal.

I have already checked the following:

Tried different pc in her room, same problem with ADSL. ( either pc doesn't cause problems elsewhere)
I have checked the wiring to all sockets and even replaced the wiring to the socket closest to her room.
None of the other pcs cause any problems anywhere else.
I have check for electrical noise on all appliances around her room.
Checked and changed all microfilters.
Removed wiring around her room, it used to run under her floor, now doesn't.
Recabled Ethernet to her room, even installed wireless card in her pc.
Tried changing her monitor.

I have pretty much exhausted all I can think of, hence the message for any other ideas ?

Many thanks,

Matt

Power off everything, and I mean everything, in the house, including lights, fridge, freezer, central heating. Then power up the Hub and allow it to settle. Then connect he PC and see what happens - if it causes a problem in her room and not elsewhere then it is further head scratching time. Then slowly bring up the other appliances/devices in or around her room ... lights, TV, curling tongs &c and see if any of those combined with the PC create the problem.

What OSs are PCs running?

Does router have uPnP ON? Try switching it OFF?

I have previously done this on the breakers to this location etc. it appears to be any pc the is powered on in her room.

As it is any PC in her room and no where else, I was thinking that it could be an intermodulation problem with noise from two sources, neither of which cause problems on their own, combining to create an inband issue which is picked up by a phone wire ...

Does the problem still occur if a computer is powered on in the room but is not connected via Ethernet or Wireless?

Does your Telephone line route anywhere near the room?

Do you have a Network Switch or an Old Router which you can put between the PC and the modem and try it that way?

Basically:

PC - Switch/Old Router - Modem


Edit: Have you tried gathering a couple of extension leads and tried plugging a computer in another room into the sockets in the problematic room?

Edited by chris6273 (Sat 18-Feb-12 15:15:35)

It sounds as if something is probably failing on the PC and causing interference/noise.
You say you've checked for interference, how did you do that?

If it is the PC it could be either the monitor or the PC itself causing the noise. So you could troubleshoot that by turning off each in turn and monitoring your router stats etc.

EDIT: Sorry re-read a bit more carefully and see you've tried changing the monitor!

When you say: "it appears to be any pc the is powered on in her room. "
do you mean when any PC is used in the room?

Edited by b4dger (Sat 18-Feb-12 17:32:50)

It seems strange that a PC in a single upstairs room causes a problem as all the sockets should be on the same ring and unless a very big house, in relatively close physical proximity.
Does leaving the PC as is but powered from an extension lead plugged in downstairs make any difference?

Now, that I haven't tried, the extension.

The pc in the room adjacent has no effect either to the ADSL or anything else.

They are both on the same ring main.

The house isn't that big, it not like the west wing or anything...

Might be worth buying one of these