[qpw]

The only way you can guarantee to do that is to reinstall windoze and remove the directory mentioned below.

However, you should be OK deleteing the directory 'Party Gaming' from the 'program files' directory and then running a registry cleaning tool.

I suspect, however, that just deleting the directory should be OK because I doubt they'll be looking for previous installs since they are not a reliable way of checking whether anyone is trying to open multiple accounts.