While I prefer Firefox and Opera to Internet Explorer, there are a few sites that just don't work with any other browser. Sandboxie lets you run IE in a sandbox, so the changes it makes to your disk and registry are not permanent -- unless you want them to be. This allows you to run IE and visit those oddball sites that insist you have to be using IE to do business with them -- with a greatly reduced risk of infecting your system permanently with malware. When you are finished using IE, you can empty the sandbox and revert your system to the condition it was in before you ran IE. All changes made by IE (new favorites, cookies, history, downloaded malware, weird modifications to the registry, etc.) go away when you empty the sandbox. Sandboxie will even sandbox other programs and has advanced features that will allow you to copy changes you want (downloaded files, new favorites, etc.) out of the sandbox so you can keep them after you empty the sandbox.
From the Sandboxie web site:
...[Y]ou may want to run your Web browser inside the sandbox most of the time. This way any incoming, unsolicited software (spyware, malware and the like) that you download, is trapped in the sandbox. Changes made to your list of Favorites or Bookmarks, hijacking of your preferred start page, new and unwanted icons on your desktop -- all these, and more, are trapped in and bound to the sandbox.
You could also try a new toolbar add-on, browser extension or just about any kind of software. If you don't like it, you throw away the sandbox, and start again with a fresh sandbox. On the other hand, if you do like the new piece of software, you can re-install it outside the sandbox so it becomes a permanent part of your system.
Sandboxie intercepts changes to both your files and registry settings, making it virtually impossible for any software to reach outside the sandbox.
Sandboxie traps cached browser items into the sandbox as a by-product of normal operation, so when you throw away the sandbox, all the history records and other side-effects of your browsing disappear as well.
Sandboxie is freeware. There is a paid version with a few additional features (e.g. warns you when you try to start selected programs outside the sandbox), but for many people the free version will do more than enough.
Operating System: Windows 2000+
Web Site: http://www.sandboxie.com/