XPAntivirus 2009 (XPAntivirus2009 or XP Antivirus 2009) is just another Rogue Application cloned straight from XPAntivirus2008. It puts a small icon in Your system bar and shows fake windows security messages to inform about "infected" computer.
These messages are being generated by a Trojan. XPAntivirus 2009 messages will urge you to download their software and will prompt you into purchasing the full version of XPAntivirus 2009.
XPAntivirus 200 is from the same family as Antivirus 2008, Antivirus 2009, Windows Antivirus 2008, VistaAntivirus 2008 and Ultimate Antivirus 2008.
XPAntivirus 2009 will start on every windows start-up and will not stop attacking You with those messages.
Remove this parasite as soon as possible.