I have been developing my forum by running it on my PC but will shortly be putting it on the web server. What is the best way to do this do I install fresh on the server with same dbname etc and then overwrite files or what?
if you haven't edited any of the .php files, just upload whatever version you've been developing with to your server.
Upload any custom images
Create the database, no need to run the install script. Make sure your config.php file is correct however.
Export your old database on your development machine, into your new database.