If that is the cloth deformer plug in, remove it. 

As for the serial and preferences, It probably has things in the registry, or in its own preference file that didn't get removed on an uninstall. 

Here is what happened when I had the sparrowhawk cloth plug in if I created a vertex object it would hang and be gone.  I removed all the third party plug-ins and re-added them one at a time until that one came up.  Not sure why but its a beta so I left it out.  Let me know if it still happens after you remove that plug in, for now I would remove any other third party ones.  Lets get you stable then can add them back in one at a time.