if your have LAN in your network and you can’t connect to your friend Sharing File or Printer, check this first :

  1.  Make sure that TCP/IP NetBIOS Helper is started, go to “Run” and write “services.msc” and then press enter.

2.  If the TCP/IP NetBIOS Helper is already started, and you still can’t connect to your friend…check if            both of you are in the same WORKGROUP

    3.  Check your Local Area Connection Properties and make sure that Client for Microsoft Networks and File and Printer Sharing for Microsoft Networks option is checked.

LAN Properties