A. What might be the problem, exactly? I don't use Ubuntu so I know nothing about their 64bit OS but, should be workable.
B. As for downgrading, no. You'll need a fresh reinstall. You can probably salvage config files from your ~/ folder to a CD or whatever media you wish. Otherwise, a clean install is all you got.
B. As for downgrading, no. You'll need a fresh reinstall. You can probably salvage config files from your ~/ folder to a CD or whatever media you wish. Otherwise, a clean install is all you got.