Originally Posted By: slolerner
Well, I had someone come in and turn off my computer and when I turned it on after getting home, it said there was no airport hardware. I ended up just opening and closing the lid a few times and the card came back,

If memory serves, in older laptops the Airport antenna is in the lid and connected airport "card" located on the logic board by a ribbon cable. I suspect the intermittent connection is the result of
  1. a damaged (frayed or.broken) cable or
  2. loose cable connector

Originally Posted By: slolerner
but was still curious why AHT wouldn't run because I knew it was built in, that is, would run without the disk. I guess it is part of the OS and not in the firmware?
AHT is a stand alone utility and not part of either the OS or firmware. Depending on the version of OS X it was either on the only install disk or the second install disk when there were two. In OS X 10.9 and later there is no AHT per.se. but Disk Utility and key utilities including an installer are on the Recovry Drive partition on the boot drive. The command+D boot works only when the correct install disc is in the optical drive.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein