Drupal Slowly Losing Functions Day by Day (clean install? and how?)

Dear All,

I am in trouble!! I have been using Drupal for 4 months now and at first, was loving it! However, my problems have been many and I need a solution! Here is a quick run down of what' been going on!

First, I was plagued by the white screen of death which has meant that update.php will not complete and I can't add or remove modules as the confirm page never loads. This has crippled my site usage but I have dealt with it in the mean time.

However recently, my menu page has lost the "add new menu item" function and i can't edit existng items (when i click edit, it takes me back to the root menu admin page. And NOW my blocks page has lost the "add new block" button and clicking edit is similar that it just takes u back to the block page without letting u edit. On both occasions the web address changes to the edit or confirm address but instead it just shows the block or menu page

Im worried now as I can't edit anything and more and more functions will go until I can't even add content!

SO, I guess I should restart right? But I don't want to lose all the content and menus etc I have already made thought at a stretch, so long as my server files and content pages/events/stories/books, remain untouched, i could redo the blocks and theming and menus myself!

Basically, I want a clean drupal install now on my server but without losing my content! How can i do this???

I am quick to learn but know little at the moment. I have access to PHPmyadmin and my server directories!

Any help would be fantastic! The site is www.exetermedsoc.co.uk

Again, thanks - Ed