When I try to shut down the computer the message from Avast says I still have a CD in the computer please remove it. I do not have one there. What should I do?
Go to the program settings, select the “Common” page and uncheck the option “Check CDs in drive when logging off” (or the two similar checkboxes around as well).
Do you use any virtual CD drive application in your system?
Did you do what igor suggested?