Loss of network connectivity

Hi, I recently purchased a Sony vaio VGN-FZ18L laptop. I've set up my laptop to connect to my network (WRT54G) wirelessly but every time I switch the laptop on or when I connect all the computers on the network disconnect temporarily. The connectivity loss lasts only 20 – 30 seconds but that’s enough to disrupt any printing or downloads. I have tried using static IP address and removing DHCP serving but nothing helps.

At the moment the network consists of
1 WRT54G router
1 HP 1320nw
2 Consoles
1 PC
2 Laptops (including the Vaio)

There were no problems before the Sony vaio

Any help would be appreciated, thanks.