changed database password and now many plugins are not working

I recently changed the database password for the site in question. I updated the password in wp-config.php and everything seemed to work fine / as usual, except after a while we noticed that Wp SlimStat, FireStats, a custom user tracking plugin and another stat type plugin are not updating with visits to the site.

I can’t figure this out and am hoping perhaps there’s something more obvious to someone else who may be able to shed some light for me…

I’ve tried uninstalling and re-installing the plugins (though I did not purge their data, as would like to hang onto that). I’ve completely re-installed WordPress. I’ve also searched through the custom plugins to make sure there is not a separate db config file -which there isn’t.

brainstorming… there is no page caching or db caching or anything like that…

Any ideas?