What ports are open on my PC?
The Netstat command can list currently used ports, which might be helpful if you suspect an application is clashing with another one on an active port. Use the -an switch to show all connections and listening ports in numeric form.
C:\> netstat -an
Check the output for any port that you think your program might use.
PING and TRACERT work because they don't use TCP/IP to test connectivity, they use ICMP packets