There are several possible causes depending on the error messages and don't forget what the cRIO status lights are doing either.
You can try the No App switch/reboot as Don suggested. This works if it's only a bad or corrupted user program at fault.
Another process is to boot in Safe Mode and reformat, followed by a non-Safe Mode reimage, both using the cRIO Image Tool. This pretty much works whatever the cause was as long as it's a software problem.
There's also the possibility that metal debris has worked it's way inside the cRIO and is causing intermittent shorts. You fix that by carefully opening and
following directions to clean out the cRIO case.