Microsoft support for Windows XP with Service Pack 2 (SP2) ended on July  13, 2010.  Support for Windows Vista without any service packs ended on  April 13, 2010.
If you do not upgrade to Service Pack 3 (SP3) in Windows XP, then  you will no longer receive security updates from Microsoft.   This is  not a situation you want to be in.
Download Service Pack 3
 
