reboot to clear the DNS cache (or clear it manualy using ipconfig
/flushdns in command prompt without having to reboot)
if you don't believe me (or want to see an example of what I am talking
about), open command prompt (start, run, type cmd and hit enter) and
type this:
ipconfig /displaydns
wow, look at that sonny boy, the computer has a DNS record for
playboy.com
you should manually delete browser information under windows explorer
too as opposed to using the browsers internet options. IE has been
known to not completely clean things out.
of course, have integrity with everything you do and you won't need to
clean it out.