How do i repair the LAN CARD

I would assume your are talking about the network connectivity light on your Network interface controller (NIC). You should have two lights on your card, one should be amber and the other green. If you are getting signal then your green light will be on and if you are receiving/sending packets then you should have a blinking amber light. I am assuming you have not manually gone into the system and statically assigned an IP address, if you have there is the problem. I have attached some "How TO's" below that should help.

Windows XP
http://windows.microsoft.com/en-US/windows-xp/help/netw...

Windows 7
http://www.dummies.com/how-to/content/how-to-repair-a-n...

Mac
http://www.techradar.com/news/digital-home/home-network...