How do software cookies get into my pC's operating system?

Windows XP offers some useful security benefits, such as Windows Update, which can be set to install security patches automatically, and a built-in firewall. However, if a user doesn't install the updates for a long time after the Windows Update icon is displayed in the toolbar, Windows will autmoatically install them and restart the computer on its own. This can lead to the loss of unsaved data if the user is away from the computer when the updates are installed. Service Pack 2 enables the firewall by default. It also adds increased memory protection to let the operating system take advantage of new No eXecute technology built into CPUs such as the AMD64. This allows Windows XP to prevent code from being executed on areas of memory flagged with an NX bit and can stop some buffer overflow exploits from running arbitrary code.