Windows 8 - Preliminary list of Security improvements
Windows 8 will provide further security improvements and a preliminary list is noted below:
How Windows 8 Beefs Up Security
QUOTE: Windows 8 promises to be much more secure than Windows 7 — so much so that some users might not like it. Chris Valasek, a researcher with the San Francisco security firm Coverity, has been playing with the developer preview version of Windows 8 since last fall. He told the British tech blog the Register that while the internal structure is not too different from that of Windows 7, there are a few new features that will nonetheless beef up Windows 8's security considerably.
App store - New Windows 8 Apps will be contained by a much more restrictive security sandbox
Internet Explorer 10 -- Locking down the browser with improved Flash & Java protection and other safeguards
Secure Boot -- It means that all installed operating systems, whether on a hard drive or on an optical drive, will be checked for digital certificates of authenticity before they're allowed to start the machine.
Windows Defender -- Windows 8 will have a Microsoft first — a built-in anti-virus software installation