Over time my various features on my Drupal sites seem to break.

My oldest Drupal site is over 5 years old, so IIRC it started with Drupal 4.something. It's now running 5.14 so there's been a couple of updates, and some of them have probably not gone as they should have. Some features that currently don't work are the aggregator (it says it's enabled under modules, it's not) and file attachments have disappeared.

Perhaps Drupal could have more advanced error detection?

How do I fix things like these? The only thing I can think of is deleting the tables associated with these modules and, well, hope they get recreated when disabling/enabling the modules. Previously I could have imported the tables from the drupal.mysql file but it doesn't exist anymore....