I have a hp mini linux, ubuntu 08.04. Of course I couldn't resist temptation for the 10.04, that I upgraded following ubuntu geek forums. I got lost in limbo somewhere when I couldn't figure what i was to follow! It is a netbook and I have 10.04 but, have an error screen when the update manager is activated.

W:WPG error: http://ppa.launchpad.net hardy release: Signatures can't be verified because the public key is not available: NO_PUBKEY3F2A5ZE4B796B6FE

I have felt petty before this learning the scripting and all and then decided to jump in head first, please help I could not figure this out now or to tell how much longer into the future to get rid of this bug. Maybe when I am more expirienced I will be able to optimize this machine before it is labled coleco.

umm goto - > System - > System Software -> authentication.

You will find a Key that resembles your error delete it.