Adobe AIR Not installed, can't install!

My security package tells me that Air needs updates, so  I must've had it at one time, but I can't install the latest version and have followed all the instructions to  overcome this - except that it can't be found!

I've been having trouble downloading stuff lately (unrelated) although I may need it to do so.

Anyone have any bright ideas? I'd be very grateful as this has been going on some time and it's beyond a joke!

Many thanks

Moot