You can also turn it off using Vista. I think you go to the control panel "System" and look for security settings. It will give you about 3 warnings before it lets you. Then it will bug you with a red task bar icon that you have to close. I found a way to get rid of that, too, but I don't remember how.
So far, no problems, but you should know how to be careful before turning it off. By the way, I bought 2 GB of RAM (2 1GB sticks) from Fry's yesterday for $14.99.
The red don’t-you-like-my-annoying-features icons in the taskbar often are from “services” (they should have call them “disservices”). So go to My Computer / Manage / Services, and look through the list till you find the one with the name that sounds right, and disable it.