Final answer:
The component that defends against spyware in Windows Vista and Windows 7 is Windows Defender. It scans the system to protect against unwanted software. Windows Firewall and UAC have different security functions.
Step-by-step explanation:
The software component that comes with Windows Vista and Windows 7 to defend against spyware is Windows Defender.
Windows Defender is an anti-spyware program that automatically scans the computer to help protect it from spyware and other potentially unwanted software. While Windows Firewall helps to block unauthorized access, and User Account Control (UAC) helps to prevent unauthorized changes to your computer, they are not primarily designed to protect against spyware in the way that Windows Defender is designed to do. Windows Antivirus is not an actual product name associated with Windows Vista or Windows 7.