To save memory and CPU time turn off the automatic update system in windows. You can always check manually for updates and most users have no problem with that. For those of you lazy bums out there you can leave this feature on but I warned you.
1. Open control panel.
2. (if using XPstyle control panel, click on performance and maintenance.)
3. Click on System.
4. Then click on the automatic updates tab and select Turn off automatic updating. If Service Pack 1 is installed uncheck Keep my computer up to date.
5. Click Ok.