Open Notepad by clicking on Start | Programs | Accessories | Notepad Click file | Open. Locate the C: Windows folder and select win.ini and open it. Look through the file and if there is a section listed as [mci extensions], then look for a line that says avi=avivideo If there is a section called [mci extensions] but no line that says avi=avivideo then add the line avi=avivideo If there is no section called [mci extensions] then add the following to the end of the win.ini file so it looks like this