Mine is Pentium(D) Dual Core with Intel Mother Board 1 GB Ram + 15" CRT
It is with Win98, XP and Ubuntu 9.04
Last time I upgraded from 8.04 to 9.04 without any problems.
Now the installation CD of 9.10 did not allow to upgrade.
I tried the update manager and commandline also and those also failed.
Finally I tried for Web Upgrade.
It went on around 7 hrs and after reboot show the following message and fails to boot.
I tried sever attempts and recovery mode. Nothing helped me.

init: sreadahead with process (2053) terminated with status 1
mountall:/proc: unable to mount: Device or resource busy
mountall:/proc/self/mountinfo: No such file or directory
mountall: root filesystem isn't mounted
init: mountall main process (2054) terminated with status 1
General error mounting filesystems
A maintenance shell will now be started
CONTROL-D will terminate this shell and re-try
root@arivukkadal-desktop:~#

Control+D did nothing.
Please help me to recover my system.

Can you try to re-install it? It sounds like there was some kind of fundamental installation error.

What do you mean by re-installation?

I tried with installation CD
When choosing the partition on which it is installed,
it warns that the installation of 9.10 will be deleted and the data on it will be lost.

I was afraid to go further.

Should I go further?
or
any other method?

With your Live CD, make another partition, ext4, and backup your data. Then make 2 partitions for your new installation one for root (/) and one for home (/home). Format them to ext4. I suggest 10G for / and something like 20 for /home.

Start your installer and choose "manual" when it comes to the partitioner. Right click on the partition you made for root and click on "change" follow directions. Do the same for the home partiton.

Install. Transfer your data.

Re-installation would be starting over from scratch, so any data currently on the partition/disk/drive would be lost. However, you said you are trying to upgrade from 9.04 to 9.10, correct? So I got the impression that the 9.10 install did not work properly, and now you cannot use it at all. If you haven't been able to use it, there should be no data in there anyway (at least not data that you might put there, such as music or word processing files, web browser bookmarks, downloaded programs and settings, etc). So if you haven't been able to use 9.10 then a re-installation simply blows away the messed up installation and you can start over.

However, if you were able to setup and use 9.10, and then these problems developed after that, then yes, there would be data in there you might want to backup.

I formatted another partition and installed 9.10 which works without any problem. I can access the data of my old installation drive.
What I want is that the entire setup of my old installation again!
It contained several installed software, fonts, etc.
I also want to know what went wrong and/or get back my old installation.
The installer detects it as 9.10 installation but unable to recover or repair it.

Good luck getting it straightened out! Sorry you had so much trouble with it (I had problems too, knetwork-manager doesn't like my wireless router).