Sorry I did not make myself clear I installed WP1.2.2 onto a separate laptop to see if I could sort the problem without messing with the original installation. With the laptop installation I then installed 1.5 to see if this fixed the problem. I copied across the database. I did run wp-admin/upgrade.php which successfully upgraded the database. Again the index.php correctly displays the blog with all the posts we have previously made but does not allow anyone to log in. Again this was tried in Firefox 1.0 and IE6