I can't purchase new apps for any of my iPads

Question

I recently tried to buy a new game on my iPad HD and after hitting the Buy button, and entering my password, the Install message pops up, but then quickly disappears - returning back to the price of the app (game).
I tried purchasing it on my 2nd iPad HD and I got the same results.
I was able to update my apps on both iPads, and even make an in-app purchase in another app (Comixology), but I can't buy a new app. I've rebooted both, logged out and back in, but have had NO success.
I have more than enough room on the iPad(s) for the game, and have enough $$ in my account.
I've tried to update my software, but it keeps telling me i'm all up-to-date.
Any help?

Answer 1

Try:
- Reset the iOS device. Nothing will be lost
Reset iOS device: Hold down the On/Off button and the Home button at the same time for at
least ten seconds, until the Apple logo appears.
- Reset all settings      
Go to Settings > General > Reset and tap Reset All Settings.
All your preferences and settings are reset. Information (such as contacts and calendars) and media (such as songs and videos) aren’t affected.
- Restore from backup. See:                                 
iOS: How to back up                                                                
- Restore to factory settings/new iOS device.             
If still problem, make an appointment at the Genius Bar of an Apple store since it appears you have a hardware problem.
Apple Retail Store - Genius Bar