ADSL shared network issues

Hi all.

We have four connections, two wireless, two wired, via a D-Link router. The other boxes are all windows, mine's the Ubuntu, running KDE. When my box is turned on there are more complaints about lag, hanging and network dropouts than when it's not. When I turn on this box, the modem needs to be reset for it to work at anywhere near speed.

We're in a remote rural area in Australia and the service is pretty crappy anyway, before the kids moved back home and this was the only box connected, there were still heaps of dropouts. I've made many calls to the ISP (Telstra) but they reckon they can't find any faults in the line and don't support Linux.

I've turned off autoupdate and set a static IP, anyone else have any other ideas? I'm working on a way to suggest separate connections but that will probably involve world war 3 due to cost, so it's on the backburner.

Ubuntu 12.04 on a quad core i5, wired, KDE.