To update any of Microsoft's products, usually go 2 xp's 'help and support', and look for the update section (top right). Set a time to auto install updates.........or go to:
www.microsoft.com/updates or www.microsoft.com and search for the particular program you need updating. The main thing is to update all your programs a.s.a.p!
The program 'advanced windows cleaner' by Iobit (www.iobit.com) has an excellent program in it called 'update notifier'. It will show you all your programs that need updating, and also take you directly to the update you need to install. i use it quite often cause you just forget.