Windows XP extended support ended on April 8, 2014. Vista extended support ended on 11 April 2017. There are security issues with both operating systems. Fastest solution is to install Java runtime (if you can find an old copy of Java runtime) and then install IBM i ACS (Access Client Solution). What version of IBM i will it connect to? Must you use IBM Client Access? If so then if you do not have it (and from what I can find it is no longer available from IBM on their FTP location) then you need to find someone who has an old copy.