Why is my computer constantly looking for networks?

That is normal behavior - as long as WiFi is on, it will be looking for all available networks. You should be able to stop it by going to Network Preference Pane in System Preferences > highlight the Wifi on left and check to see if "ask to join new networks" is checked. Uncheck that and see if that stop the search.

I did that yet my MAC is still "Looking for networks"

Well, I believe the answer you would be getting from Apple is that "it is working as intended". Why is it bothering you? Is it hampering whatever tasks you are trying to perform? If not, just ignore it - my Macbook is constantly looking, but I don't notice it because I am not constantly monitoring that activity by going to the pull down menu to check it.

Hello! My computer is doing the same wifi 'looking for networks'; it wouldn't bother me otherwise, except as it is searching, there is little or very slow internet connection. It is quite irritating. Ideas?

This is normal. Your device is NOT constantly looking but only looks again when you click the airport icon. You may want to change networks or you may have come into the range of a new network that was not previously in the list, you see.

This is the case whether the box is checked or unchecked pertaining to "asking before joining new networks" in the system preferences.

Think of the light which only comes on when the refrigertor door is opened.

No its not resolving the present problem !!