Had this problem on a Windows box I have to admin.
The Symantec Anti-Virus Corp Edition was broken, and I'd followed the instructions from Symantec.
But, every time I did a right click I got "please wait while Windows Configures Symantec Antivirus" and after a bit "Gathering Required Information" and then it asked for a CD.
To fix this you can download the installer cleanup from Microsoft support.microsoft.com/kb/290301. Ignore that it says for Office - works great for all installers!
Run the installer. It told me that a Symantec Install was stalled and asked if I wanted to undo it. So I did, and then installed the tool.
Run it, and scroll down to find Symantec, and click remove. Job done!