Try disabling client-side negative DNS caching as well.
How to Disable Client-Side DNS Caching in Windows XP and Windows Server 2003
I've had this fix a lot of similar problems with laptops running on wireless networks installed in less than ideal conditions. (ie manufacturing plants)
How to Disable Client-Side DNS Caching in Windows XP and Windows Server 2003
I've had this fix a lot of similar problems with laptops running on wireless networks installed in less than ideal conditions. (ie manufacturing plants)