"Save Configuration" in Drupal 7 Module not visible I inherited a customized Drupal 7 site and am trying to add some things without a lot of knowledge of how drupal works (I have general html/css/JS, and some classic ASP, .Net experience).  I was able to install a couple of modules (Widgets, Widgets Service Links, Widgets Services  - for Social Media buttons) but can't seem to enable them.  They have dependencies with each other, but they are all there.  I can click the check boxes but I see no where to save the enabling of the modules.  According to what I see out there, there should be a Save Configuration button, but it is not visible to me.  We have a couple of security updates that we haven't done, but when we did these previously they mucked up our configuration so we decided to hold off on them until we know what we're doing a bit more (we were able to restore from a backup).  Could the security update alerts be preventing the saving of modules?  That's the only thing I can think of other than our whole configuration being messed up somehow?
Sounds very much like a custom module is hiding the module save button to stop people adding/changing things. I've had the misfortune of inheriting sites with these sort of "security features" before too. 

If you do have any custom modules installed. the simplest thing you can do to test is get Drush installed, run drush dis CUSTOM_MODULE and check to see if the button comes back. Then you'll know if it's the custom module's fault at least. You can also disable them manually in the system table but you should only do that if you really know what you're doing.

The upshot of that is you can also use Drush to install the other modules outside of the UI, so even if that's not the problem you'll still be able to install new modules.

Also, to find out if a change to core files is responsible for the problem, grab the Hacked module and run a report. If you install the Diff module along with it you'll get a side-by-side diff of exactly what has changed in core/contrib modules.