TheChas answered correctly. However, the Security Center will still be started each time you boot your machine. If you are using your own firewall and anti-virus and you routinely do updates then you do not need this service at all (I have disabled it on all my xp machines). Here's how to completely disable the Security Center from running at all:
Press the Windows and R keys
> in the resulting window type services.msc
> in the resulting window scroll down to Security Center and double-click on it
> In the "Startup type:" box use the arrow to scroll down to choose "Disabled"
>click Apply and reboot, or, click Apply and click the button that says Stop.
This is just another option for you.
Cheers.
RW