i have ubuntu 11.10 installed within windows vista. i am trying to upgrade it to 12.04. but the update manager seems to be stuck at "Installing the upgrades" while configuring manpages. i did a restart but after which my wi-fi driver was lost. after the restart, it started witing 12.04 but my wi-fi driver which i had installed was not to be found. now what to do.it did'nt upgrade fully.
If it where my desktop/laptop I would ... Backup user data to external storage and to a fresh install.
If your wifi adapter isn't working with a fresh install, then I'd do a 'lspci' and find the wifi adapter model and google that + ubuntu 12.04. It's almost certain that someone has already solved the issue for you. But I can't tell because you didn't post a lot of details other than a failed upgrade.