Windows Update
You have just finished building your new computer or reinstalling Windows and connect to the internet to begin downloading all your favorite programs when your machine is attacked and is left unbootable. This is of coarse the worst case scenario but hackers are a reality and can happen to you within minutes of being connected to the internet, so take some extra precautions. In XP make sure that your firewall is turned on (until you can download a better one) and update Windows first. To update windows just click on Start then on All Programs and up near the top you will see Windows Update.
Now after several restarts and updates you will be much safer on the internet, but there's still more to do next you must install an anti-virus program and update it as well.
Windows Genuine Advantage
Windows genuine advantage or WGA was launched as a way to prevent pirated copies of Windows XP from receiving all the benefits of a legal copy of the software. If you wish to download optional updates or Beta software you will need to validate your copy of XP. If you choose not to validate your copy of windows, you will still be allowed to download critical and security updates. Once the WGA check has completed and you discover your copy of windows is not valid you will be given several options to validate your software and a "NAG" will appear in the bottom right of your screen. To remove the "NAG" do a search for the program "removewga.exe" .