Over the years I have used ubuntu's software in its various releases. I still consider myself a relative noob. However, my question and problem pertains to the ongoing software updates and eventual version upgrades. Through each version of the Ubuntu system I have always enjoyed using the software until boom! I do an upgrade and it will not boot. This happens to me on different machines and different scenarios including dual boot systems and single boot systems where linux was the only OS. I always find myself having to start from scratch with a fresh install after an 'upgrade' trashes something. I have not been using Ubuntu/Linux for the last year or so because of this problem.

So, I suppose what I want to understand is the proper way to approach the whole upgrade/update deal. I wish I could understand better what the OS is trying to do that always causes this problem for me. Should I never do an 'upgrade' and simply do fresh install instead with each new release? What is it about the upgrade process that I have to be careful of?