I am very happy I found this topic, because I have been trying to find answers to an almost identical question the last week. Please allow my to semi-hijack this tread and make it more informative to other members with some added questions (and hopefully answers).
My questions concern the change from CMS (Joomla to wordpress), while keeping the same URL. Unfortunately I have not created my new (temporary address) website in a sub domain, but rather on a test domain. so this is my first question:
1] Are the steps above also valid for moving between two unrelated URLs (say, from test.domainA.com to domainB.com)
My next question concerns the use of the dreamhost webFTP. I used that since it came recommended, but probably I did not do it right. In step 2 and 3 I need to rename the relevant folders (move domainB.com to domainB.com.old, then create a new clean folder "domainB.com", and one-click-install WP in the folder. When I tried that I received an error saying "Joomla! has already been installed at http://www.domainB.com". I got around this by removing the joomla installation in domainB.com via the user panel.
2] Is there a better way of doing this? And why did I receive the error when following the steps described above?
When following step 6 (changing the URL in the WP dashbord of the old site (test.domainA.com), I changed both fields (the wordpress address and the site address). This resulted in a then dysfunctional old website. In the end what I did was first following step 7 (renaming the old directory (test.domainA.com) to the new directory (domainB.com). Afterward I edited the wp-config file by adding the following lines:
3] Did I mess up step 6? Should I only have changed wp OR site address? And is the hard coding both addresses via wp-config going to bite me in the ass later on?
I hope you can help me, I look forward to a reply. Thank you!