Try to install the latest recommended build of Bukkit or the Vanillia.
Then try to catch your ip, then make an dyndns ip so it will be the same.
Things that may crash it could be plugins, or the portforwarding.
Do to the CMD, type in:
Ipconfig
Search for an error, it could be Hamachi, if your Gateway, standard Gateway will be repeted, thenn u got the error.
Delete that error program (Will stand over the repeted Gateway)
