CP100 Call Center Stops Processing

I have a site where the CP100 Call Center has been working for years. Recently they have been having problems where the call gets locked up in the queue and doesn't present. When the one agent logs out and then logs back in, she gets the call and things start working again temporarily. I've changed power supplies. Deleted the agent and created a different agent ID and still the same problem presents. Just weird. Have done a backup of the programming and was going to put it in another CP100 and see if it does the same thing. This would tell me if the unit or the programming is corrupt. Not sure if anyone else has encountered this type of problem and can say they found an easy way to fix it rather than wiping the slate and starting over. Also, I'm under the impression that if I was to wipe the slate on this unit, I would end up losing the Call Center activation code? Seems to me doing a voicemail reset does this, but leave you with the 10 Vmail seats only? Let me know. Thanks!