If it only does that when not in "Safe Mode" then you have something on the tablet that is the cause. Virus, malware, bad app, etc.
You will need to locate the cause and remove it to make the tablet work correctly. Or, you can do a "Hard Reset" of the tablet, but that completely wipes the system, so you would need to save what you want from it first (files, music, photos, etc., but not apps, can't save apps) off of the device to a cloud account, google account, computer, etc., and then do the reset.
NOTE: Doing this will clear 'all' the data on your tablet, so it is suggested you not choose this option unless you have to, or aren't worried about losing anything on the device.
Be sure you back up any data you want to keep, to a...