Moving wordpress from subdomain to root directory

I originally installed wordpress just to use the blog feature so installed it in the subdomain of /Blog. I’ve now decided to build the whole website with it so want to move the files to the root directory. I changed the urls and moved the files to the root directory but it all went horribly wrong and my website was lost for about 9 hours and I couldn’t access the wordpress admin until I deleted then reinstalled all the files back in to the /Blog folder. I’m hoping that someone can help and talk me through it really slowly as I can’t work out where I went wrong.

Also my website is now automatically directing to http://www.drawnbyrhiannon.co.uk/Blog which is handy in a way as people are being directed when they type in http://www.drawnbyrhiannon.co.uk but I just don’t want the /Blog in every address of the website!

Thank you very much in advance to anyone who can take a minute and be patient with me to explain this.

The page I need help with: [log in to see the link]