I've been upgrading Ubuntu since 8.04. I never did a clean installation after that. Recently my laptop is booting up extremely slow. It takes more than 150 seconds to boot up. How can i make it faster? I'm attaching the boot chart. Is there anything unusual which is slowing down the boot up?
Thats one mean and big boot chart. There are also several process that are taking WAYYY too long to finish. My guess would be that there are still several things that got mixed up between upgrades. Did you check your Startup Applications:
System -> Preferences -> Startup Applications (UnCheck the ones you are sure not to use)
After that check for installed programs that you REALLY do not need.
But seeing as your tag says 11.04 am guessing you are using Ubuntu 11.04. Because this version is not yet finished or even RC you WILL have a big change to find problems when loading, using it, playing with it, etc... I do not recommend an Ubuntu version until it is ready. This is because of things that still need more work on, missing fixes, etc..
I suspect the ACPI. If you do not explicitly need it. You could shut it off from the Grub-menu or in the BIOS.
The Grub way: You will need go into edit mode by pressing E from the Grub menu boot selections. At the row that say