I cannot find AirDrop anywhere on my computer?!?

Finder Preferences, Sidebar.

Is AirDrop selected?

Note that it only works on newer Macs that have capable WiFi cards.

See here if that is the case: http://hints.macworld.com/article.php?story=20110913213649565&query=airdrop

How old is your iMac?

The hardware that AirDrop leverages is only present in 2009 and newer iMacs:

http://support.apple.com/kb/HT4783

How old is your iMac. If it isn't within about a year or two, it likely doesn't have the necessary WiFi card. See the link I posted to use it over your network, instead of ad hoc WiFi.

The hardware that AirDrop leverages is only present in 2009 and newer iMacs:

Ok, three.

Message was edited by: Barney-15E

It waid i could type a phrase into a terminal window....What's a terminal window.

Terminal is the command line application. It is in the Utilities folder which is in the Applications folder.

Copy the command and Paste it into a Terminal Window and hit return.

Then log out and back in.