asoroka :
first I assume that all pC's are on the same LAN.
Turn off your window firewall for all networks (public, work and home) then try to ping each machine.
as already said by the previous guy, try to ping your machine to the other machine by doing the following:
Find your pc's/laptop's IP Address
Step 1) go to the other devices and Go to: Start -> Control panel -> Network and ethernet -> Network Sharing Center -> on the left click change adapter settings -> then right on the icon where you are connected to the internet -> click in status -> then click on Details. note the IPv4 Address of every pc.
Step 2) when you got all the ip addresses, go to your own pc/laptop and do the following: Start -> Type in CMD (no need for administrator rights) -> and then enter in the box: ping "IP Address", but enter the address after the ping without the quotes.
let me know how the result went