This typically happens when there is a windows updates that puts the A2D2 software in remote viewing mode.
To put the software back into acquisition mode do the following:
1. Close the A2D2 Software
2. Hold down the shift key on your keyboard
3. While shift is pressed open the A2D2 software
4. A dialogue box should appear asking you if you want acquisition mode
5. Select Yes
6. Your software should now be in acquisition mode.