I've update to linux-image-3.2.0-30-generic-pae 3.2.0-30.48 and now Ubuntu don't open smoothly and take time to boot but it's not that weird because I had this problem when I was using 11.10 all the time but some how when I upgrade to 12.10 it fixed, so now after I got like 3 new kernel images update the problem got to back again, what I'm asking here is how to bring back the old linux-image to system and you must know I have remove all the old kernels with Ubuntu Tweak janitor option so now only one I got is linux-image-3.2.0-30-generic-pae 3.2.0-30.48.
Just install the Linux images again
sudo apt-get install linux-image-3.2.0-23-generic-pae linux-headers-3.2.0-23 linux-headers-3.2.0-23-generic-pae
You should now have option for booting the previous Linux image. Boot to that image and remove the updated one.
If you really want to get a list of all Linux images, You can check the repository pool by going here
A screenshot is added below: