Converting WordPress Categories to use 'Pages'

I have had a WordPress theme designed and installed onto my server and it uses the Categories and Posts functionality of WordPress. However, I need to remove the above functionality and NEED it to work with the 'Pages' function of WP, so that it is more like a CMS and not Blogging type website. the author, images, and flash movies need to be uploaded aswell, so this functionality must remain. There are approximately: - 6-7 main pages - 5-6 sub pages within each main page - possibly 5-6 sub pages within that... I need this to be completely editable using the WP admin, so that I can delete and add new pages. All the design is done, so am looking for an expert in modifying and customising the programming side. I also need you to install a good plugin and give me advice on how to use it for managing adverts around the site. People with WordPress experience only please guys. Thanks.