If you have an SD card installed, try removing that and rebooting the tablet. The next option would be to download the latest firmware and install it per the guides on this forum.
It sounds like a corrupt file and a reinstall will fix you up.
Reinstalling the latest firmware manually will not destroy your data. If these solutions don't work, then you may be out of luck. Did you back up to any cloud services. If you use a web based mail service all the mail is there. If its docs and pictures then as I tell many people, if its that important you need a backup of your backup. Tough Lesson Learned.
Sent via electron magic. My opinion is my opinion and any solutions or ideas probably have a hundred ways to arrive at the same result. Unless you pay someone to provide the right answer, you get what you get. Free advice is often worth what you paid for it.