By default, Internet Explorer 9 keeps a history of visited websites for last 20 days. Here is how to change the time period for which history of websites is maintained :
1. Select the gear icon in Internet Explorer and choose Internet options.
2. Under the browsing history section, select Settings.
3. In the History section, change the number of days from default of 20 days next to option of days to keep pages in history as desired.
All done.