Big Brother and Ndisuio.sys A new Internet phenomenon?
Ndisuio.sys, a very mysterious system file is present in Windows XP and is a driver for wireless things such as wi-fi and bluetooth. However, there have been many issues with this file downloading immense amounts of data and perhaps causing activity that is "big brother"ish.
The fact that hardly any information on this file downloading data is available by Microsoft makes things quite suspicious about it. It has even been noted that it looked as if it was transferring data to major companies like Comcast, Road Runner, Time Warner, BTC and Verizon.

But duplicating this data can hog resources for no reason, so disabling it is the best thing to do. The data rate of this file's received data is huge, so that indicates that the data transfer is not over the Internet, but locally. So it's just a duplicate of network activity but because it's local everything transfers faster but uses more resources then casual internet usage as there's more data involved at a given time span of 1 second, for example.
To disable this file, go to the control panel, administration tools, services, Wireless Zero Configuration, double click and disable it. This file is probably required to run if you use any linksys wireless devices.