1
Click "Start." Click "Search." Click "Tools." Click "Folder Options." Click the "View" tab. Click "Show hidden files and folders." Uncheck "Hide extensions for known file types." Uncheck "Hide protected operating system files."
2
Click search in "All Files and Folders" in the "C Drive." Type "index.dat" into the search bar. Click "Search."
3
Download and install an index.dat file reader onto your computer if you don't already have one. Open the index.dat file within the reader. Click on the history you would like to restore to select it. Click the "Restore" button to restore your selections. Open your Firefox browser to check the restored history.