iCloud Backup Message on iPad -- not responding

I have a message on my iPad --> "This iPad hasn't been backed up in 2 weeks. Backups happen when this iPad is plugged in, locked and connected to WiFi"..Then OK button.

The OK button does not respond. The iPad has a full charge, is connected to WiFi and is locked. I can't clear the iCloud message. I have attempted to turn off the iPad but as you know, you press the button and then slide the 'slide to lock' bar. I can see it behind the iCloud message box but it does not respond. I have it plugged in and 'meeting all of the requirements' on the pop-up but no luck. I also attempted to connect it to my PC, back it up and wipe it to factory but iTunes is not recognizing the iPad. The PC is showing it connected as a new external drive. I've searced online for an answer and now I am here. Short of taking it to the Apple Store, is there anything you can suggest? It is an iPad 2 - 64GB, WiFi & 3G.

Thanks!