Under normal circumstances you create user accounts for "Users" not PCs - is that what you did using the Dashboard? To make it seamless to access shared folders it is best to create the same user name on WHS as you have on your client PCs and use the same
password. If you change the user password on the client you should only need to use the Dashboard and do the same on the server - if that dies not work there is another problem
Phil P.S. If you find my comment helpful or if it answers your question, please mark it as such.