Exporting site when getting a 500 error and cant use export tool

Hi

Have been working perfectly until about 2 weeks ago.

I upgraded to a newer version of web matrix and then wp 3.5.2

Dont know what went wrong but since then every time I try to go to the site I get a 500 error, CGI handler problem etc. Can’t fix it.

So I looked at the export tool that would move my pages, plug ins, customisations, themes etc etc from out of the broken site and into a new WordPress installation.

Problem is that the export tool is only available if you can get into site admin, which of course I can’t !

So can anyone suggest a way of doing what the export tool does but step by step manually? Or some other way to export the site to the new installation

I’m not very technical but even if I screw it up I am no worse off than I am already

Thanks