Updated WP-Config and Site Wants New WordPress Install

I use the same mysql user on more than one site. One of my sites under this user was hacked. I successfully repaired damage, cleaned files, changed mysql user password, upgraded wordpress (2.9.2), updated wp-config file with new settings including new security keys. That site seems fine now.

However, all of my sites under that mysql user now need to have the wpconfig file updated. With the first one I worked on, I updated the wpconfig file with the new mysql settings. I tried it both with and without a new set of security keys. When I tested the site, it behaved as if wordpress had never been installed. Not sure what to do, I upgraded all wordpress files and that didnt work. I am in the process of trying to figure out how to install my backup files.

My question is this: why did updating the wp-config file with new mysql user info result in the site not recognizing the existing wordpress install? Does it have something to do with the new security keys I added to the hacked site’s wpconfig file which shares the same mysql user? If so, do I, 1) add the same security keys to each site using that mysql user or 2) generate new security keys for each site using that mysql user or 3) something else?

I have some other sites to update and don’t want to repeat this mistake. Thanks so much, I’m in a little over my head.