Possible Duplicate:
I upgraded from an alpha or beta - am I up to date if I keep upgrading?
How to upgrade to 12.04 beta 1 from 12.04 alpha 2?
Possible Duplicate:
I upgraded from an alpha or beta - am I up to date if I keep upgrading?
How to upgrade to 12.04 beta 1 from 12.04 alpha 2?