Since moving house in October I've had an O2 wireless box pushing out a wireless signal for the laptop internet and the xbox ethernet cabled in.

When we moved O2 cocked up and sent us another wireless box which has sat unused ever since.

I've managed to lay my hands on an old desktop which had a half decent processer and RAM but no network card.

Network card purchased I planned to use it as a downloading mule using the second O2 box as a plain jane router for the incoming DSL signal.

However it would appear that everytime i plug it in the 2 boxes conflict with each other messing the DSL signal up and knocking both networks to pot. Unplug and switch of one box the other works fine, swap them over and the other one works fine, both together and neither works.

Will the purchase of a standard non-wireless emitting router sort out the problem?

Is there something that will take the feed from the incoming DSL and plug straight into the ethernet connection on the network card??

Check that they're both not trying to control the network by issuing DHCP commands (turn it off on the 2nd one) and maybe they're both transmitting on the same channel?

You can't connect 2 boxes to one broadband connection...Best option is to get a wireless card for the Desktop or powerline adaptors if the signal is no good. The O2 box has O2 firmware on it and i don't think that it can be set up as a wireless bridge from the existing router (this would save you buying a wireless card then).

Best bet is to just get a PCI or USB wireless adaptor and bung it in. A TP Link one from Amazon is around £6 delivered. I have used these in the past and work fine.

http://www.amazon.co.uk/TP-Link-TL-WN350GD-54Mbps-Wireless-Adapter/dp/B002H0UW7M/ref=sr_1_46?ie=UTF8&qid=1302554142&sr=8-46

I had a USB adaptor one that did the trick but it got "donated" to the inlaws.

I assumed that an ethernet card would be the cheapest replacement, and faster than a wireless card, but clearly O2 had other ideas.

I may be able to lay my hands on a wireless adaptor for the xbox and then simply relocate the O2 box from the front room to upstairs or i guess it'll be a wireless card

Only thing you could do, would be to use the second box as just a wireless station repeater for the areas of your house where the signal is weak.