How can I clear the DNS cache?

type cmd

Windows usually caches the DNS records for faster resolution of web pages, at some point one needs to refresh that cache, this is how you do it,

Open the Command Line Interface of Windows, (Run -> type cmd)

and run the following command.
ipconfig /flushdns

http://umairj.com/92/how-to-clear-your-dns-cache-in-windows/

For Windows XP , Windows 2000 and Vista.

Go to Start Menu - Click on Run option
Type in the Run text box - ipconfig /flushdns