Click on tools and select delete browsing history from within ie7.
You can click on the My Comuter icon.
Right click on my computer and select properties.
Select disk cleanup, all users.
The computer will scan the harddrive and give you a list of options.
Select the temp Internet files.
IE7 has a reset button in control panel-internet options-advanced(tab)-reset Resets all toolbars as well so you might need to reinsatll the google/yahoo etc toolbars