upgrade or install?

I ran into some problems with my fan no longer working, possibly damaging Ubuntu to the point where I am asked to remove some old and unwanted kernel images before I can proceed, but I have not been able to do it using janitor, synaptic, and the terminal!

So, I want to make a clean upgrade or a clean install. It probably won't fix the fan issue, but I do not have the original windows XP recovery disk to dual boot, so...

I thought I did a clean upgrade when I moved from Oneiric to Pangolin last week, but obviously it was not a clean upgrade! What should I do to make it so? How should I respond to the messages that will make it so when I upgrade? Or should I just install Pangolin?

It still is your choice. Usually you can fix things but sometimes that takes longer than just a clean install.

But a clean install means you have to have good backups which you should have anyway. I cheat with a large drive and keep my old install and do a clean install into another 25GB / (root) partition. All data is on other partitions which I link back so I can boot either system.

https://help.ubuntu.com/community/rsync
https://help.ubuntu.com/community/CronHowto
Oldfred's list of stuff to backup May 2011:
http://ubuntuforums.org/showthread.php?t=1748541