July marks the end of life of two versions of Windows : XP with Service Pack 2 and Vista with Service Pack 1.  

Both XP and Vista are still supported but only if you have XP with Service Pack 3 or Vista with Service Pack2.  Service Packs are free to download.

http://windows.microsoft.com/en-nz/windows/help/end-support

When Microsoft stops supporting a product they stop releasing updates for it.  Updates are the first line of defence in securing your network.   It is therefore very important that PC’s, laptops and servers have the latest Service Packs installed.

Your Engineer or Account Manager can arrange to have your network checked to ensure you have the correct versions.