Can not press install at all?

[DRD Skid Row]

Why hello there. I am facing a pretty frustrating problem with my GS4. I have recently tried installing an application from my Phone's storage, but guess what. It would not let me press Install. It does literally nothing whenever I press it.Cancel is working fine and so does scrolling up and down. Allowing installation from unknown sources is checked and I also tried it with older .apks that I had downloaded and installed but I got the same result. Tried rotating to see if it might be a problem with the screen, nope. What could it be? Is anyone else experiencing this?

 

[B. Diddy]

Welcome to Android Central! Do you have a screen dimming app installed, like Screen Filter or Twilight? In my experience, this can grey out the Install button when trying to install apps from the Amazon Appstore, so I wonder if it could be causing your problem as well. If you do have a screen dimmer, either turn the brightness back up to full, or temporarily deactivate it.