Back in the day I really, really loved XP (still count it as one of the best OS’es Microsoft ever devised). I know that it’s still widely used. However, the good days of XP has come and passed I am afraid. Any XP machine caught on my controlled networks immediately have all network access severely limited. Suggested work around for mission critical applications that have no developer and run on XP are to be sandboxed through a VM (and even then network connectivity is still limited).
Reason is, except in rare government cases, Microsoft is no longer pushing out security updates since sometime last year, and any machine running XP is already considered compromised and completely unsafe.