I had a problem with my copy of Parallels ufter upgrading last night – the shared networking no longer worked and it was grabbing the same ip as my Mac – causing all kinds of problems.

The program wouldn’t allow me to re-configure the network settings (all other options were greyed out).

So after a lot of messing about, I decided to uninstall Parallels using the Uninstaller which ships with the app, delete all Parallels files (except the .pvs) and re-install.

This solved it completely!