Invalid redo in checkpoint record

Hi,

After a recent server crash after which the whole system hung and power had
to be pulled, I'm having the following error pop up when trying to start the
DB:

* Starting PostgreSQL 8.4 database server
* The PostgreSQL server failed to start. Please check the log output:
2009-11-26 16:00:23 GMT LOG: database system was interrupted; last known up
at 2009-11-25 17:37:07 GMT
2009-11-26 16:00:23 GMT PANIC: invalid redo in checkpoint record
2009-11-26 16:00:23 GMT LOG: startup process (PID 3126) was terminated by
signal 6: Aborted
2009-11-26 16:00:23 GMT LOG: aborting startup due to startup process
failure
[fail]

This is on Ubuntu 9.10. I've since tried to reinstall Postgres via Synaptic
(using complete removal), but I'm getting the same error.

The data is unimportant, so is there any way of getting the server itself to
run again? I've been advised to create a new cluster, but if I can somehow
reset or recreate the default one that'd be the best option. Otherwise I'm
considering reinstalling the whole shebang which seems a bit drastic.

Thanks!

Shak