I cannot tell exactly when this happened, but surely after upgrading to Ubuntu 12.04, but on my last bootup it lasted from selecting the distro on the GRUB menu to full usability 4 minutes 22 seconds to boot! (not taking account of the time that I type the password on login screen). A few things to clarify:
1) This never happened before 12.04.
2) I have a HDD with 2 partitions:
a) an NTFS where W. XP sits
b) an extended partition where there are three logical partitions
i) a 19 Gb where the filesystem sits ii) the linux swap iii) an NTFS partition
3) I know that this could be solved like making a fresh install or such but I still trying to find a way to fix this without reinstalling anything.