Reset Internet Explorer settings

Internet Explorer can be difficult to troubleshoot, partly because of the many settings and modifications that can be made to IE. Also, if Internet Explorer gets infested with malware (perhaps I should say when instead of if,) it's good to have a way to undo as many changes to IE as possible and roll it back to a "factory-fresh" configuration.

As it turns out, one of the less-documented features of IE7 is a function that allows you to do exactly that: reset Internet Explorer to the state you'd have on a clean install. Microsoft calls it Reset Internet Explorer Settings (RIES).
To access RIES:

    * In IE, select Tools | Internet Options.

    * Under the Advanced tab, click Reset.

    * After you click OK to close everything out, close IE; the settings will be restored the next time you launch IE. You can also do this from the Internet Options portion of the control panel.

Note: While most of IE's settings are affected by RIES, some are not. RIES will disable all third-party toolbars and add-ons and will remove all temporary files, browser history entries, cookies, Web form data, passwords, proxy information, search providers and homepage entries. However, it does not affect one's favorites (i.e., bookmarks), Internet connection settings, Content Advisor settings or Group Policy entries.

For instance, if you have a problem that might be traced to a Content Advisor level being set too high for a given site (e.g., disabling JavaScript), RIES won't help. But RIES should be able to deal with any problems that arose due to malware or page-hijack exploits, and it's a good first step when debugging a chronic IE problem.

Note: Since the settings are applied on a per-user basis, you don't need to be logged in as an admin to run RIES. It only resets the settings that apply to the current user.
source: techtarget.com