I installed AVG Free on a Vista HP PC, with what I believe to be the default configuration. I believe it is performing a full virus scan every morning. When I had AVG Free with Windows 98 I think all it did was a brief boot up scan but I had to initialte a full scan myself, which I did about once a month. Is this automatic daily scan desirable, and if not how often should I do a full scan? In the meantime, anyone know if AVG Free will still detect and clean a bad file at the time it is viewed (on the web, for example)? Thanks in advance.

You don't have to do full scans everyday but I would recommend you to process a full-scan every week. This daily scans are scheduled and you can change the settings that are more favorable to you.

AVG can detect a file before you open because it uses "resident shield" for real-time protection!;)