Dell KACE Secure Browser (74 Mb):
Description:
"Using virtualization technology, the Secure Browser prevents any changes or malicious files downloaded from the Internet from corrupting the underlying Operating System present on the computer."
Download Page (free pre-registration required):
http://www.kace.com/products/freetools/secure-browser/
Screenshot (from the developer):
http://www.kace.com/img/content/products/freetools/secure-browser.png
Freeware Overview:
http://www.kace.com/products/freetools/
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(Initial source of info: freedownloadaday website).