My parents told me not to pull faces otherwise it might stick like that ..... they were right ... one flippant bit of typing ..... and Andrew's has been stuck since 2009

Someone not called Matthew mentioned about ports and they might be onto something

If someone starts changing port numbers on the server maybe that is where the problem has come in perhaps because there does seem to be a link/association with the instance name, possibly to the point that server name is mapped to IP address and instance name is mapped to a port so the instance you were using may or may not be on the port you thought it was or the instance is mapped to a 'problem port' (blocked by workstation firewall) or summit loike that