Why preferences doesn\'t work ?

I have read previous topic, but this solutions are
not effective.

Best Regards,
Dominique.

Can you tell us what you are trying to change that doesn't seem to do what you want? This may help people to guide you.

The other thing you might try is to look at <a href="http://homepage.mac.com/pauldbuck/site-boinc/faq/faq-over.html">Paul Buck's site</a> which explains the BOINC software in detail.