How to get default desktop from partial install?

[PaulJ at netcall.com.au]

I've recently changed distros to Ubuntu 6.10 from Fedora FC6. I scrubbed
the "/" partition but wanted to preserve the existing "/home" and
"/usr/local" partitions from Fedora as they contained a lot of good stuff.
Everything went well except on boot-up the desktop is a mess lacking the
proper default set of menus etc. I presume the set-up for this is stored
in my account somewhere and has not been overwritten by the new install.
My question is: how do I reset the desktop to be the standard Ubuntu
desktop as if from a completely clean install?
Thanks,
PaulJ.