I would like to thank all those who helped me. After several sleepless nights trying to figure out what went wrong, I just decided to unintall and reinstallthe whole WP software. I am now wery reluctant to install any plugins. I am crossing my fingers. It will be useless to have a blog software installed that you can’t use. I am however confident that the developpers will find a definitive fix for the problem, and not only some partial fix.
Thanks again.