I have just accidentally found out another way to give you an extra boost in windowsXP's boot performance. This is done by disabling your unused devices in Device Manager. for example, if you don't have input devices that are connected to one of your USBs or COM ports, disabling them will give you an extra perfromance boost in booting.
Go to Control Panel - System - Hardware tab - Device manager Disable devices that you don't use for your PC and then restart. See the difference for yourself.
Bonus Tip: Perform a Boot Defragment
There's a simple way to speed up XP startup: make your system do a boot defragment, which will put all the boot files next to one another on your hard disk.
When boot files are in close proximity to one another, your system will start faster.On most systems, boot defragment should be enabled by default, but it might not be on yours, or it might have been changed inadvertently.
To make sure that boot defragment is enabled on your system, run the Registry Editor and go to:
Function Edit the Enable string value to Y if it is not already set to Y. Exit the
Registry and reboot. The next time you reboot, you'll do a boot defragment.
" Windows XP Tips: Disabling Unused PORTS"
Reference : techpraveen.com