i need help in ethernet sheild

hi everyone

i'm new in this field and i'm trying to use Ethernet example "webserver" 1- watched this video in youtube:http://www.youtube.com/watch?v=nYzEbEOMGuo 2- tried to do exactly what he did and changed MAC address to same as mine ethernet 3- uploaded to example to my arduino uno r3 4- entered the ip to the browser 5- but it shows "Oops! Google Chrome could not connect to 192.168.0.* " 6- also i tried yaler.net account and their example but same issue. i tried diffrent arduino version of ide's (1.0.2, 1.0.5 and 1.5.5) but same problem

how there missed step ?? how can i know if there is problem in my arduino ethernet sheild ??

please help

What is the ip of the computer you are using for the test?