Finding an active ip address

i downloaded 2 ip scan programs. i know how to search for ip addresses but i cant seem to find active ones. im trying to find ip addresses that i could use for (nbtstat -a ipaddress)
can somebody please tell me a quick way to find ip addresses that are sharing files.

 

Is that on a local network or over the internet? coz if its on the local network you can use "net view \\ipaddress" to see what shares there is.