Web browsers such as Internet Explorer (IE) and Firefox have a large number of add-ons available through the internet to increase or enhance functionality. Unfortunately these add-ons can cause IE and Firefox to slow down or become unresponsive during use.
How to Resolve this problem
How to Disable your Browser's Add-Ons
To reset your Internet Explorer settings, you need to click the 'Tools' menu tab (or the star settings button) > 'Internet Options' > click the 'Advanced Tab' > then click the 'Reset' button. (Use the "Delete Personal Settings" check box if you have no personal settings such as cookies which you need to keep, as this may also help towards solving the issue)
You need to click the 'Help' menu tab > click the 'Troubleshooting Information' > 'Reset Firefox' button.
Both of these methods will keep your Bookmarks or Favourites.