Can't delete Relation module I'm trying to disable or delete the Relation module (and about to pull what's left of my hair out).

Relation and Relation Endpoints Field are checked, but greyed out so I can't uncheck them. I don't see anything that's dependant on these, and I don't see anything in the Field List related to this module.  

All of the other Relation modules (Relation Dummy Fields, etc) have been uninstalled and I've run cron 40 or 50 times as well as 

DELETE FROM field_config WHERE field_config.deleted = 1;


which someone suggested on another post on the topic, but no success.

The reason I'm trying to delete Relation is that I'm trying to update Drupal core from 7.28 to 7.36 (long story) and getting an unresolved dependency as Relation isn't compatible with 7.28.  Someone suggested I disable the module before doing the update, and I'm trying to do that.  However, I'm wondering if per-chance this problem has to do with the incompatibility.  

I don't seem to be able to move forward or back and I'm not sure what to try next. 

Currently:
Drupal 7.28
Relation 7.x-1.0-rc7
One thing to check is if there are still fields using this field? Take a look at admin/reports/fields to see if there is anything using the relation fields.

Once you are certain...

If you are certain that there are no dependencies relying on this module, then you can open phpmyadmin, and look at the system table.

Look for /sites/all/modules/relation.info and change the status from "1" to "0". Do the same for relation endpoints as well.

This will disable the module manually.

I would recommend doing a good backup, or even better, recreate your environment away from your production site and test there.