Comment 3 for bug 1072311

You may find some valuable info in bug #930447 including links to two 12.04 non-pae images.

I've personally chosen to stick with Ubuntu 12.04 which is supported until April 2017 on my non-pae machines using the options I discussed here:

http://ubuntuforums.org/showthread.php?t=1959675

I even put up a thread about using Gnome classic (no effects) in 12.04:

http://ubuntuforums.org/showthread.php?t=1966370

That's a good solution for me for the next 4 1/2 years ;^)