How do I remove extinct clients from basic, free, Hamachi networks when the PCs no longer functioni

How do I remove extinct clients from my basic, free, Hamachi networks when the PCs themselves are no longer functioning  ???

I have long since dead and gone, PC's that were once part of my Hamachi VPN network. 

Now the PCs are dead and gone and I cant add new working PCs to my Hamachi VPN networks because the dead client names are occupying network slots.

The dead PC Clients do not appear in my LogMeIn website online Netowrk management account.

Thanks.