I can now startup the database even though I am still prompted for a password.
Here is what I had to do in the end.
De-install the Oracle software using the Oracle Installer (after stopping any services if you managed to start any!).
Remove the Oracle directory.
Remove any entries in the Registry.
Remove the Oracle branch from HKEY_LOCAL_MACHINE | SOFTWARE
Remove all Oracle services from HKEY_LOCAL_MACHINE | SOFTWARE | CurrentControlSet | Services.
The Oracle Installer should have removed Oracle entries in the Win98 environment. If not do so!
Re-install Oracle 9i
Change the SYS and SYSTEM passwords when prompted by Password Management Tool (I made them both the same!)
Now use the new password when starting up the database.
Curiously, during installation, towards the end there is a part, which claims to set the Startup Database Auto, even though this succeeded, I am still prompted for a password when starting up. Very strange! I’d be interested to know if this happens to you as well!
Also because I used identical passwords for SYS and SYSTEM (and in all honesty being a bit of a novice with all things Oracle), I am not entirely sure which password is used to start up the database – SYS or SYSTEM (or both!), I’ll look into it a bit more another time, or perhaps one of the guru’s looking in might be able to help!
In any case, after days of tinkering with it the thing now works!