Folks,

We are missing on one thing to answer to all your questions. He couldn't start the listener. So as a result, you cannot do a tnsping.
The best route to these is
0. Make sure that tnslsnr file exist in your $ORACLE_HOME/bin
1. configure the listener.ora and tnsnames.ora file using the Network Configuration Assistant (netca).
2. Then try restarting the listener.
3. Then make sure that the network is up, by pinging.
4. Then try the tnsping
5. Then try connecting.

-Sam