Ok, I've tried once already to install Leopard from an upgrade disc, having previously been using Tiger. The first installation didn't work, giving me an error message along the lines of 'couldn't find a previous installment of 10.4'. Now I've backed up all my files and performed a clean install of Tiger, and this time "sucesfully" completed the Leopard upgrade, BUT NOW I cannot even get past the loading page, ie. Apple logo and the little swirly thing below it. The screen has been like that for 20 minutes and I've restarted a couple of times with the same outcome. Can someone please help?