Clear your history. To clear links from browser, right click on blue part of the taskbar and click properties, then select start menu, then customize. From there you can delete your used programs list. Then click on advanced and then click on clear lists to clear the list of most recently opened documents that should include your links in the browser. Might be good to do a search for cookies just to make sure there is not another folder somewhere. Then run disk cleanup just to top it off.
Here's a link for more info on
Microsofts really hidden files
Might be better to just to show her how much fun adult sites can be.
Good luck!