Every users hits a point when AutoCAD displays a dialog box alerting you to something and you see the check box that says something to the effect of "Don't ask me again" and that box gets checked.
Many people have enjoyed the not being bugged afterward, but occasionally there is regret.
Here is how to erase that regret.
Go to the Systems tab of the Options dialog, and click the "Hidden Messages Settings" button.
This will open the expected dialog revealing everything you have chosen to hide. More importantly, you can choose to see the regretted dialog boxes of your choice, by checking the boxes next to them.