My guess is that the download connector doesn't fit quite as tight in the hole on the Aeris 2
as it used to.
First, if you are running 2.x ACI, look at the top line of the download dialog window.
(The one that comes up after you click [+] and select your computer type)
If you see: "USB Interface NOT FOUND", in red you have a connection issue
between the PC and the download cable or a USB driver issue.
If you see: "USB Interface FOUND", then the PC sees the USB data cable
and its not a driver or USB issue.
Aeris has a nice trouble shooting guide to aid with resolving this issue:
Aeris USB not Found Trouble Shooting Guide
If the connection to the Dive computer is loose or there is some water on the
contacts that detect "H2O" mode, you will see the behavior you are experiencing.
Check the "springiness" of the pins on your USB connector.
With the USB cable disconnected, push on the 3 little pins in the connector
that attaches to your dive computer and make sure they spring back into position.
You could try pushing/holding the connector in the Aeris with a slight
pressure to see if that improves the connection.
I have to do this sometimes on my wife's Aeris AI.
Just a few ideas.
--- bill