I finally got the guts to pave my machine and install Windows Vista.  I'm pretty particular about backing up all of my settings and documenting what I have installed but there is always one straggler that I forget about or didn't backup correctly.  This time it was Hamachi.

If you're not familiar - Hamachi is a free VPN service and the Wikipedia entry is pretty good at describing it.

If you want to keep your existing Hamachi IP and settings - BACK UP BEFORE YOU REINSTALL.  Otherwise, it's too late to do anything.

I was in the "too late to do anything" crowd.  During the re-install of Hamachi the start up screen told me I needed to startup Hamachi so I can get a Hamachi IP address for my machine.  There was no option to enter my settings from a current account.  This was my indicator that I had done something wrong.  I powered up Hamachi, got a new IP, and joined my network.  However, now I had a machine in my network (the old one) that I couldn't do anything with and it just happened to be the "owner" of the network so I couldn't remove it from the network either.

I only have a few machines in my network so it was easy to create a new network and move the other machines over.  I would hate to have had this problem on a larger network and have settings configured to the IP addresses.

Hamachi support forum with the details
Hamachi How-To backup your settings

Giddy Up!