Why can't I open either Candy Crush or Candy Crush Friends?

Hello @Krystofer - I'm sorry to hear that you are experiencing this problem.  Have you made sure you have the latest versions of each app and have you cleared your cache?  Once you have done that - turn your tablet off for at least 10 seconds and when you turn it back on see if that helps.  The other thing is these games tend to be very sensitive to having a strong and steady internet signal - so make sure you have a good connection.  (Please forgive me if I am telling you to do things that you have already tried).
However if that still doesn't work then the only solution may be to de-install and re-install the games.   However, - if you do this you will lose all your lives and any saved boosters you may have!  This should only be done as a last resort. In my case that wouldn't matter for CCF because I don't store boosters or lives but in CCS I definitely do.  Any gold and boosters that you have purchased should be saved and the studios should be able to restore them for you if necessary.
Hopefully you have been playing either thru Facebook or king.com - that ensures your progress can always be retrieved.