Stopped Services making laptop unusable

I accidentally turned by computer off during a Vista update (when it says Do
NOT turn your computer off). Now, only about half the services start,
Explorer won't run, Live One Care won't start (I get a window saying it
cannot start) and I can't open Control Panel . I tried a System Restore but
the same problems persist. At this point I just want to get all my data off
and reinstall Windows but I can't connect a back up or run any installation
software for backups.
Has anyone got any ideas on how I can repair windows outside of a system
It's Vista Business with SP1 (not sure what the update in question was but
SP1 installed fine previously)
Thanks in advance