How to clear DNS Cache

Vista, Windows 7, and WIndows 8

These same directions work in versions of Windows after XP; however, you’ll need to gain admin privileges first:

XP

XP remembers negative (DNS unable to resolve) entries for a few minutes. Often this can be a pain when moving and debugging sites. As long as that negative entry sits in your DNS cache, your box will continue to give you a cannot find server error. By cleaning out your DNS cache, you can fix this problem.
Rebooting will flush your cache… but there is an easier way.
Drop to a command box and type:

ipconfig /flushdns

If you wish to stop XP from placing negative entries into cache, you can make this change in your registry.

1. Goto HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ Dnscache\Parameters 

2. Build a new DWORD value called NegativeCacheTime and give it a value of 0
I believe the default time is 5 minutes. I always use zero for my default time, but I think the value above is in seconds. So if you only want to save them for 1 minute, then I am assuming you would change that value to 60.