upgrade Ubuntu 10.04 to 11.04

When you install a LTS release of Ubuntu it defaults to only offering upgrades to other LTS releases. So the next will be 12.04.

You can change this by opening Update Manager, settings, and browse the tabs until you find the checkbox that says - only offer upgrades on LTS releases.

But if you do this you will first have to upgrade to 10.10 and then upgrade to 11.04. This is no direct way to go straight to 11.04 from 10.04.

Some users have problems with upgrading so it's advisable to make sure your backups are current before attempting. Also, note that hardware that works with 10.04 may not work the same on later releases. In particular, Wubi users have had problems booting Ubuntu following the upgrade (and/or overwritten the windows bootloader)... see http://ubuntuforums.org/showthread.php?t=1639198 for description of the problem and fix. (This only applies to the 10.04 to 10.10 upgrade).

In some cases it may save time to download the alternate desktop CD image for the release you are upgrading to and run it from there - you don't boot from the CD, you just load it and run the upgrade from it. See https://help.ubuntu.com/community/MaverickUpgrades (section: Upgrading Using the Alternate CD/DVD )

If you installed with Wubi - which it seems like you did as you posted your question in the Wubi section - that's about it for options. It may be simpler to save your /home, save a list of software you have installed and then just install a fresh 11.04 and copy over /home and reinstall the programs. If you would like to know more about this, let me know.

PS before upgrading make sure you read the release notes.