IE
1. Open IE, look for File in the top left or a gear tool icon in the top right
2. Under General it should say "Browsing History"
3. Click Delete/Delete All, then select all, then either delete or Ok
Firefox
1. Click the top left that says "Firefox"
2. Click "History" then "Clear recent history"
3. Time range should be "everything" and all the boxes should be checked. Then click "clear now"
Chrome
Go to this guide written by Google
here
If you use Opera then it should be similar to Firefox.