How to replace an old version of Ubuntu with a newer one from USB/DVD?

Solution 1:

The first thing you should do is backup your data.

• Then download the iso of 12.04
• burn it on a disk or usb.
• After that you can boot in the live CD/USB and select install
• During the installation you will be prompt either to replace or upgrade
• Select Erase Ubuntu 11.10 and reinstall.

Solution 2:

To answer your question:

First, prepare a bootable USB stick with Ubuntu 12.04 on it. Then restart your computer and boot on your stick. Select "Try Ubuntu without installing". When you see the desktop, launch the app called "Gparted". This will permit you to format the partitions where you previously installed Ubuntu.

However, from another question you asked today, I think that what you want to do is install Ubuntu 12.04. If this is true, then you don't have to worry about erasing the previous installations. You have two possibilities.

Either you boot into Ubuntu 11.10, you search for updates and the Update Manager will propose you to upgrade to the newer version. Or you boot on the 12.04 USB stick and you follow the instructions. Be sure to check "Format drive" when you see it. The first option will permit you to keep your documents, settings and installed programs.

Solution 3:

First, I'd suggest making the Live CD as mentioned. Be sure to backup what you have, if there is anything you don't want to loose. Next, boot from the CD and pick to try 12.04, and make sure it works well for you (no issues/incompatibilities, etc).

Then, you can either choose to do a clean install (letting it erase 11.10), or, what I do, install 12.04 along side of 11.10. After the install, I boot up to 12.04, install the apps I want, and mount the partition for 11.10 so that I can copy over stuff from my home directory.

Finally, after I've spent time with 12.04, making sure everything is cool, and ensuring I've got everything off of my 11.10 home directory, I do a backup, use gparted to remove the 11.10 partition, resize the 12.04 to use up all the space, and then use the grub2 steps to update grub and it'll remove the unused boot choice for 11.10.