Question : Networking issue caused by adding a Sony laptop to network

Small home/office network. One PC cabled to Belkin pre-N router and four PCs and laptops (mixture of XP and Vista) connected via wifi (WEP only). All working happily until new Sony SR39XN laptop running Vista is added. Whether the new laptop connects over wifi or cabled connection it brings the speed of the network down. ping returns that are steady at 25-26ms to a known UK site increase to arouund 38-50ms  on enabling the network card on the new laptop and if I try to run Windows update then almost immediately the ping returns increase until the downloads start when the ping returns change to "Request timed out". Stopping the downloads does not get the ping returns to resume, but if I disable the new network card then the ping returns resume at 25-26ms almost immediately.

The problem is 100% repeatable, I will try on another network in case it is network specific but it does seem to be new device related.

Answer : Networking issue caused by adding a Sony laptop to network

Actually it was just a NIC driver issue. So problem solved.