Increasing LAN speed

First go to the properties of the nic card and check the box under the general tab that says "show icon in notification area when connected".

Now you will see a computer icon in the lower right corner of your screen. Place your mouse over it without clicking. You should get a ballon that tells you what it is and the speed.

If 100mb then its not your lan but, most likely, your internet connection.

If 10mb in the same network properties and then nic properties you can set the speed and duplex of the nic. 100mb and full duplex.