Question : Desktops running Great Plains Dynamics lose connectivity but can still browse network

We have two desktops on XP Pro latest service packs and they have Great Plains 10 installed on them.  They are accessing the GP server on the same network, same subnet.  They will work fine and then all of the sudden in the morning they won't be able to access Great Plains Dynamics but will have internet access and access to our file servers and other services on our network.  We have to do an ipconfig /release and then renew to get the GP stuff to work again.

When it's not working we can still ping the GP server.  The GP server has SQL 2008 Server installed on it as well.  We can still browse the server by going to \\SERVERNAME\

Why would we need to keep doing this and only on two desktops when the others all work fine?  The two machines are on different network ports and they do not break at the same time.

Answer : Desktops running Great Plains Dynamics lose connectivity but can still browse network

Since this is working properly on all other computers except these 2, I would start by trying to determine what is different about these computers.  OS, service pack, other software running (particularly AV software)?  Next I would check if the ODBC's are set up differently from your other computers.  Are you using a different version of the SQL driver?  In general, I have found SQL Server to be more 'stable' than SQL Native Client, however, if you are using functionality that SQL Native Client is needed for, you may not be able to switch.  Might be a good test, however, if only to rule it out.  

Also, is there anything in the Windows event log of these 2 computers that would indicate any kind of network or connectivity issue?