Cannot Activate Plugins or Themes

I am not sure what’s going on, but when I select a theme in the presentation screen it will not activate this is also true for my plugins. Now it has been the case since this started happening a couple hours back, that the theme will finally switch on about 10 min. later. For awhile no theme was showing up, deleted a bunch of themes that I thought might be the problem but I am not sure what else to do.

Does anyone know what’s wrong or how to fix this?