Negative DNS

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. The easier way is 

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.