On restarting after a blue screen I got a message about system32 being missing and did I want to auto repair the registry file. So I said yes. The result is that on starting outlook (office 2003) it runs the outlook setup wizard and asks me to set up a new profile.
Scanning my hardrive for PST files finds my August 2005 back up but there is no trace of anything more recent. Last used outlook successfully yesterday October 2 2005. I can't believe I am going to lose all my September emails which I spent a lot of time refiling!