Basic system changes can increase stability and speed.

Lock the sawp file: A single continuous Page file is best, set at 1000MB. After locking the Page File, defrag it w/ PageDfrg (www.sysinternals.com)

Desktop Tuning: Reduce the Gucci Factor:
In XP & Vista System applets, the is a performance page that lets you modify the various graphic enhancements. Set the radio button to: Best Performance then apply.
Then Turn OFF "System Restore" and "Remote Access" reatures in the System Applet.
In the Display Applet, turn OFF "Active Desktop"
(aka "WEB" tab in Display Applet. Cannot be disabled in Vista) Use an image viewer (Irfanview or XnView) for setting background images.
Audio: Using the Sound applet, disable all unneccesarry sounds.

Startup Apps:
Cleaning unneccesary programs from the startup list. This is usually done in the registry and SHOULD NOT BE PERFORMED BY A NOVICE! The theory is: Every Ounce Counts
(old racing saying) Why have programs running in the background that you're not using? ie: scanners usually leave several monitoring programs running at all times, even if you only use the scanner once a week, or month. Perhaps you never use the OCR function.