Ubuntu upgrade problems (from 10.10 - 11.04) at "Installing the Upgrade stage"

It seems like there is some sort of IO problem preventing it from extracting the contents of one of the packages it's trying to install. When this happens while installing or upgrading packages it usually is the result of a process being locked indefinitely in uninterruptible sleep. This sort of problem often results from a kernel bug and I'm not aware of any generally effective way to solve it besides rebooting. If you don't understand some or all of the above, don't worry--there are easy-to-follow instructions below.

"I am afraid that I may crash the linux if I restart the linux, what do I do now?"

You're right that it's possible that if you reboot, your system may not be usable. For that reason, I recommend you make sure that all your important documents and any other files you need to have immediate access to have current backups, in case you have a nonfunctional system when you reboot and have to go through the process of fixing it (or of performing a fresh installation).

Then I recommend rebooting and attempting to resume the installation. If you experience further problems, please post a reply here.

This happened to me, i was 18 minutes remaining and it crashed, i had to turn off the frozen screen and i lost everything. My pc now a shell unable to do a thing. Im now on another pc.. i cant use windows im so used to ubuntu. Now running on 8. something im trying to upgrade again to where i was (this time ill stay on 10.10 though) im getting errors already :(

@Bharadwaj Jaya
Are you still experiencing problems?

@sarah jackson
I recommend that you post a new question; while your problem started like Bharadwaj Jaya's, it has apparently taken an unfortunate turn for the worse, and is now a separate issue from this question. (Your problem is much more likely to be due to your computer being powered off, rather than the update itself being interrupted.)