I'd like to remove the preview that appears on the left part of the explorer when I click on avi files. I know it is possible to remove it if I do not use the "Web view" of my browser, but I want to keep this preview for the pictures.
I assume I have to change a key in the register, but I don't know where!

Tools > Folder Options > On the General Tab under Web View click "use classic"

This is the only way I remember that turns off the preview pane on the left. You can preview pictures by telling that folder to Thumbnail items in the Views panel.

That's the solution I know

Maybe this tip can help you change the default folder template:

http://snakefoot.fateback.com/tweak/windows/tips.html#WEBVIEW_FOLDER

Thanks a lot!
It works perfectly