[ubuntu-uk] Truly, a vanilla install

[Rowan Berkeley]

I seem to have done one stupid thing: trying to get embedded YouTube
videos to play in the Firefox browser in Ubuntu 8.10, I installed two
plug-ins one after another, neither of whiuch helped at all One of them
can be disabled (though not uninstalled),via Firefox > Tools > Add-ons,
namely Gnash 0.8.4, but the other one seems to have vanished into the
Firefox configuration without possibility of disabling or uninstalling,
namely SWFdec 0.8.0, and I would like to get rid of both of them and try
again, since right now any attempt to run embedded videos just hangs the
browser, so that I have to use a forced close on it. I have not tried to
alter or remove the video player utilities that came with the Ubuntu
8.10 LiveCD, which is otherwise running perfectly. So, any advice on how
to roll back these (or all) add-ons and plug-ins I myself have installed
today would be great. Thanks.