Support for Windows XP Service Pack 2 ended on July 13, 2010. Customers need to be on at least Service Pack 3 now.
http://support.microsoft.com/gp/lifean31
Likewise, Extended Support for Windows 2000 Professional is also over.
http://support.microsoft.com/gp/lifean35
If you need more guidance on support scenarios regarding these operating systems, check Eric Ligman’s blog post from June 16, 2010 here.