Ping error 1231 in Vista

Have you had an error 1231 when using ping on Vista. We had our second case of this on a laptop today.
The laptop was brought in because it could not connect to the internet. We did all the usual things, turning off firewalls, checking connection settings, we changed between dynamic IP address allocation and fixed IP addresses.
On our network we have a mixture of fixed and dynamic addresses all of which work OK. We use our domain server as the first DNS server in the chain. We have done everything right. Yet, no internet connection.
If we used fixed addresses we could see other systems on our network and ping them but not those outside. With dynamic addresses we got the error 1231 if we tried to ping anything including local addresses.
We spent almost 3 hours today searching a number of support fora (even the Microsoft tech help forum) and have put in place a number of suggested changes. One suggested change which we could not put in play was to change the graphics adapter card so we had to keep the Nvidia card that comes with the machine.
None of the suggested changes made any difference. It became obvious from the posts in forum after forum that there is no single way of removing this error and I even doubt if any one has really found a fix for this.
In the end we had to advise our customer that we needed to do a 'back to factory settings' restore of the machine as the most expedient way to deal with this problem.
My issue is this. Why is it that an organisation such as Microsoft with all the resources it has to offer is unable to come up with a fix for this and get rid of it? Similar problems have existed in every release since Windows 2000 so it has been around for quite a while and should have been fixed by now.
If anyone has this problem Google "ping 1231 vista" and look at any of the sites that are listed.