updating Ubuntu

If you mount the alternate ISO you can upgrade to Lucid using that.

You also might consider simply wiping your disk and installing Ubuntu 10.04 LTS Lucid (or a later version: Ubuntu 10.10 Maverick or Ubuntu 11.04 Natty) from scratch. You can also upgrade in the Update Manager, without any disc--it will download the updates over the Internet.

The problem you were experiencing was probably never due to having a bad CD, and since everything you did to try to work on the problem was based on the idea that you had bad CD's, you were probably never working substantively toward a solution. I understand this was not your intention, but you were, in effect, doing the same thing that didn't work, over an extended time. (That tends to continue to produce non-working results, no matter what operating system you do it with.) If for some reason the above methods (including the one actionparsnip has suggested) are unsuitable, please describe in detail how you were attempting to use the CD to update.

Inexpensive Windows 7 is beyond the scope of this forum--you may want to ask on a Windows forum. If you are a student or faculty member at a college or university that buys into Microsoft's volume licensing program, you may be able to get an cheap, non-infringing copy that way.

You have already asked several questions on how to upgrade your 8.04 system to a higher release, but all these questions seemed to have died away (sorry if it was the supporters' fault).

There definitely are possibilities to upgrade your system and we are prepared to guide you through that process if you want.
You have to be aware that we need your cooperation to give answers on some questions, and you have to understand that in some cases it will take some time that you get a response from the supporters, because most of us do that voluntarily in their free time without getting paid for it.

If you want us to help upgrading your system from 8.04 (I think that is your version) to 10.04 LTS we need a few answers to start:

please open a terminal (ctrl - alt - t) and issue the following commands

lsb_release -a
uname -a
cat /etc/apt/sources.list
cat /etc/update-manager/release-upgrades

Then select all output in the terminal (edit - select all) copy it (edit - copy) and paste it into the 'Message:' box of this question document https://answers.launchpad.net/ubuntu/+source/update-manager/+question/166587

A rather easy possibility to upgrade from 8.04 to 10.04 is to download the ubuntu 10.04 ALTERNATE CD .iso file, burn it to a cd (or mount -loop the .iso file directly) and then use the upgrade script on that CD.

Do you have an internet connection where you can download that file?