router help

[Jungle_Jim]

ok need a little help guys i just got a new router through from sky as the old but the new one seems to be rubbish. i have one pc downstairs which is connected to it via ethernet cable, then 2 pc's and a ps3 that connect wirelessly. however with the new router whenever someone using the wired connection it stops the router giving out any wireless signal and all other connections are dropped.
any help would be great as this is seriously annoying
cheers
James