Something has gone arye in our network. The network engineers still have not figured out what. In trying just to get things back and workable someone tried setting his mtu=1450, he said he ran into a similar problem but it involved a firewall issue and this got them around it. When we tried it it worked! but now I have 200 pc's that need to be changed - and today the other 12 hospitals in our network are seeing the same problem so the potential number of affected pc's is many times more!