No internet access after crash - Error87: The parameter is..

Archived from groups: microsoft.public.win2000.general (More info?)

Hi
I am running Windows 2000, and experienced a crash this afternoon whilst
upgrading a program. After the machine restarted, I was unable to re-coonect
to my broadband provider. I have deleted all connections and created anew,
but each time after waiting at "Verifying username and password" for quite a
long period of time, I get the error message as shown in the title, i.e.
"Error87: The parameter is incorrect"
Any idea what I need to do to cure this? Many thanks!