How do I make my internet connection work!?

[Sign I]

I have three computers at my house, and the computer I am using now is the only computer that has a working internet connection.

Through control panel, I have tried about everything in the 'Network Connections' from repairing to trying to set up new network connections through the wizard.

ERROR:
When I try to repair the Network Adapter connection it says the following:

"Windows could not finish repairing the problem because the following action cannot be completed:
TCP/IP is not enabled for this connection. Cannot proceed."

It has nothing to do with enabling or disabling the connection through the Network Adapter because I've tried that several times and nothing works.

I can't find where to enable the TCP/IP.

Help!!!
Thanks!