If you don't intend to share media then you should adjust the settings to exclude WMP (Windows Media Player) from being shared across the network.
That should free up some resources.
I have a new computer running Windows 7 and another computer running XP on the same home network. After I started using the new Windows 7 computer, the XP computer has a huge networking problem. All the CPU resources are now being used by a program called wmpnetwk.exe. This may be related to me responding positively when the XP computer asked me if I would like to do something like share my media (music) files with the Windows 7 computer. The XP computer becomes useless when this happens!