when i was using windows, i used non-free programs for that purpose
(cracked, of course; no big risk here in india). none of them were
particularly easy to use, though.
again, depending on the original format, you might find online services
that allow you to upload videos and convert them to the more common
formats--but that requires a decent internet connection.
otherwise i don't know and would be happy to hear what others recommend,
also for linux far as i can see, video editing in linux doesn't work so
well yet. was using kdenlive, which kept crashing every few minutes...
ys phani.
you can edit in native MPEG format and save without re-encoding.