Games, security software and popular business programs are clashing with Microsoft's long-awaited security update for Windows XP.
Since SP2 was released to business users, reports have circulated about programs behaving differently once the upgrade is in place.
http://news.bbc.co.uk/2/hi/technology/3570636.stm

XP SP2:
http://www.microsoft.com/windowsxp/sp2/features.mspx
Pop-up ads blocked
Revamped firewall on by default
Outlook Express, Internet Explorer and Windows Messenger warn about attachments
Origins of downloaded files logged
Web graphics in e-mail no longer loaded by default
Some spyware blocked
Users regularly reminded about Windows Updates
Security Centre brings together information about anti-virus, updates and firewall
Protection against buffer over-runs
Windows Messenger Service turned off by default