Are you sure your on the LAN and the same subnet. Could be a number of things. Though you'll probably find its a security precaution. I use a program on all my LAN's which make each computer invisible to the other.
Im assuming your just not getting a ping reply. If this is the case, it could be firewall settings. Ping the ip and ping the name (only if you have reverse dns set-up).
Go to this site and see shutting down computer through lan by scrolling down: http://www.suhas-tech.blogspot.com
It might have something to do with Wake On Lan, this is something that can be disabled in the BIOS. try to disable Wake On Lan or WOL within bios and see if that fixes it, it so, download a bios update
color
no but there is an app that let you see what others do on their computer
The simple answer is that a LAN user (client) will not see all of the packets on the Internet; they will only see the packets for their own LAN segment.
People cannot see what your are browsing as long as you do not have any Trojan on your computer.
If using a switch, it shouldn't see any. Switches don't broadcast data to every computer connected, only the intended computer.
Actually Every part of the computer is seen and can touch called the Hardware. Software is the Intangible.
see: Difference_between_LAN_and_WAN
You can look on the back of the computer to see if there is an RJ-45 jack. This is where you would plug in an ethernet cable. It looks like the telephone jack only slightly larger. Or, right click on "My Computer", select Properties, Click on the Hardware tab, click on Device Manager and see if there is anything listed under Network Adapters by clicking on the + sign.
You can compare the features and prices to see if a computer fits your needs. To see what other users think of it, you can consult various online forums that have reviews of the computer and others from the same manufacturer. (see the related question below)
honk your horn