For modern users the most understated yet useful feature that Service Pack 1 for Windows XP provides is USB 2.0.Compared to USB 1.1 2.0 provides huge speed improvements and compatibility with many devices that require that speed to best work (USB headphones for example).Combined with the right drivers SP1 makes Windows XP compatible with many many more peripherals in one sweep.Odds are if you have an XP machine Service Pack 1 for Windows XP is already installed.This means that the problems that are fixed in a service pack are also fixed in later service packs.
Download it now to ensure that your Windows XP is fully updated.
Service packs are usually numbered, and thus shortly referred to as SP1, SP2, SP3 etc.
Service Packs for Microsoft Windows were cumulative through Windows XP.
You can easily copy all your files to a CD or another computer on your home network.
Also, keep all your original Windows and program installation CDs in a safe place. Look at it this way: Any file you cannot afford to lose (what will take too long to re-create or is unique and cannot be re-created), should be located on two separate physical media, such as on two hard drives, or a hard drive and a CD.