Thank you, twobob, inspired by your reply I was able to fix the launcher menu by deleting the extensions folder completely, then creating a new, empty one, and finally uninstalling and installing again the glauncher package. In
this post silver18 reports a similar issue which he fixed by installing glauncher manually. As regards the landscape orientation upon rebooting my K5 I found
your post and added the orientation command to /mnt/us/.bashrc. I still wonder what got the default orientation changed in the first place. Perhaps ixtab knows better as
this thread seems to suggest; but since he's busy I'll save my question for better times.
Thanks again for your help.