Once again, I am confused by Windows. Where's the talking paperclip when you need him to share his wisdom with you?
Updating Windows has always been a tough decision. Once a friend updated Windows and then he could only have three explorer windows opened at the same time. Once a friend updated windows and then he had to recover his data with the help of a company specializing in burned drives. And of course, once you've updated, you'll be constantly nagged to reboot until you reboot.
While none of the above is pleasant, the alternative has just gotten unimaginably worse as a new vulnerability has seen the day:
On Microsoft Windows 2000, Windows XP, and Windows Server 2003 systems, an attacker could exploit this vulnerability without authentication to run arbitrary code.See the Microsoft Security Bulletin for more details. And update your windows now. Or wait for arbitrary code to be executed on your computer. Or congratulate yourself having chosen a safer operating system.