Sorry for probably duplication but I am not technically minded so I do not understand most of the other posts.
I used to have a website hosted by Spruz - I have exported the user data in CSV files. I want to import this data into my Joomla site (hosted by 1and1) so users of the old ste can log in to the new one without signing up again - I have contacted 1and1 multiple times but I haven't got a helpful answer yet.
Any advice is greatly appreciated.
If you are not technically minded, then you are going to have to use a third party extension to do this. There are a few here:
http://extensions.joomla.org/extensions/migration-a-conversion/users-import-a-export
Make sure your csv matches the format they require.
If you want to do it manually with a database query, then the users table is where most of the data is stored, but check out what all the other tables starting user_ are saving when a user is created, as you may need to link their id to their usergroup or profile.
(Unless they built your site, then it is very unlikely that web hosts will help with any questions about the website's content. You may need to hire a developer to help you if you get really stuck.)
