Chnaging WordPress Directories

Hi, I had a wordpress installation at yoursitedomain.com/news/

Now I wanted to change the directory to yoursitedomain.com/blog.

So what i did was enter the admin panel yoursitedomain.com/news/
and enter the new details for the new site url and blog address.And then i clicked save.

I then went into my ftp client and rename the folder from yoursitedomain.com/news/ to yoursitedomain.com/blog/

Now when i try to view the page yoursitedomain.com/blog/ (new directory)
I get a blank page, even when i try to view the admin area: yoursitedomain.com/blog/wp-admin

What can I do to fix this?
Thank you for your help…