The laptop can see both computers and can 'see' Desktop2's files and can access them but to access Desktops 1's files it asks for a password? Goodness knows what password, I've tried them all

Desktop1 can only 'see' itself and it's own files.
Desktop2 can 'see' both computers but no-one elses files.
Can anyone pleeeeeeeaaaaase help me??
