It sounds like you're having a bit of a similar problem to me (see my thread entitled 'Recovering emails in Outlook Express after a user profile corrupts').
I've tried finding an old email folder by searching for files with the .pst extentsion but with no luck. I'm at work and haven't tried this yet but I'm told that if I'm using Outlook Express (which I am) ...
"you can use the import mechanism - need to point it at your old profile (when you said corrupt....) - somewhere like C:\Documents and Settings\username\Local Settings\Application Data\Identities\{90B064F5-7B44-4C16-A65B-4907C3746B7F}\Microsoft\Outlook Express, where username is your old profile username."
Like I say, I've not tried this yet.
'Hope for both our sakes that this helps!
Mata